I keep varieties of prepared veggies on hand at all time. I also save bones from all my cooked meats and make broth by the gallon. Not only do the veggies lead to smarter "snack attacks", but anytime I need a meal on the quick, I have instant soup.

Another great tip is to make hardboiled eggs in a big batch, then store them in the fridge for a quick and portable protein.

To keep potatoes (sweet or otherwise) from browning, just keep them submerged in water.

I don't have many tricks. I like cooking with ground beef/turkey/chicken because it's quick.

I batch-wash and prepare salads for the week, and break out my crock-pot for slow-cooked meals on busy nights.

I was about to suggest the same trick for potatoes- keep them submerged in a bowl of water.

I've also never had an issue with a 24-hour (+) marinade.

Grate lemon zest and keep it in a baggie in the freezer. It's great to add it last minute to salad dressings, fish, chicken, or pasta and for some reason, anytime people see lemon zest on a dish they're always super impressed (at least that's been my experience)

The main thing is having an arsenal of recipes you love, can riff on, and take 30 minutes max to prepare memorized. That's what makes dinner prep quick for me.

A couple of other things: getting some good knife skills and having sharp knives (I love my husband, but he takes at least 2x the amount of time to chop veg as I do because he simply doesn't have the practice); I make veg stock from my frozen trimmings while I'm boiling water for pasta or simmering dinner and by the time we're ready to clean up from our meal, I have a pot of stock ready for the freezer; and washing lettuce ahead of time--if I don't do that, I simply don't use it.

One "convenience food" I use is peeled garlic cloves. You can freeze them, and if you do, they go through your garlic press (another time saver) like a charm.

Oh! and I'm sure everyone knows this one but when you make stock, freeze it in ice cube trays in the fridge. That way, when you want to make a soup or sauce more complex you just add a cube of your stock. Be sure to label these well though! My husband has put an ice cube of fish stock in a glass of water on at least a few occasions!

Submerging potatoes in water works fine for a few hours, but if you do it for a whole day, the starch will leech out of them and the texture will be ruined.

Meat and marinade for more than 24 hours is not only okay, but usually awesome. The only precaution is to leave out the acid ingredients for fish and seafood.

I've used "omelet mix" made the night before with reasonable results, but I found it didn't save much time the next morning. Mind you, I'm only cooking for two.

If I'm being really good and planning my meals for the week, doing most of the prep work on one night helps a lot. I've been known to dice a whole bag of onions and just scoop out what I need.

My sister would always bring a big back of stuff to chop at lunch and do that on her lunch hour.

Definitely agree with the caramlized onions tip above--I freeze in small baggies, super handy. Also, pesto frozen into ice cubes are great for making a quick side dish with little effort. I like to make a big batch of meatballs and freeze them--sometimes raw, sometimes already cooked--then they're quick and easy to cook/heat up to make a pasta or veg-based dish a little heartier. I also recently discovered that you can freeze cooked bacon and then reheat it in the microwave--maybe not the best if you're eating "straight" but super handy if you're using it in another dish.

Oh, and with the potatoes/sweet potatoes question: depending on what you're going to do with them, they might actually keep better cooked. Like cut up and boil them the night before, then at mealtime saute to warm and crisp them. Kind of like making hash.

I've been roasting big batches of skin-on, bone-in chicken and then taking all the meat off and either using it for the week in different preparations or freezing it (and the bones and skin for stock).

There was a post about celery going bad before it gets used a while back and I had that happen to me. A whole head of celery got slimy in the crisper before I could use it. So I bought another head today (since soup weather is upon us), but I'm going to chop it all up and freeze it in small baggies to use for soups, since that's pretty much the only thing I use it for. My mom also used to freeze chopped carrots and onions. Since they're so small, they don't take long to thaw.

You could also pre-cook beans and either can them yourself (if you have a pressure-canner) or freeze them.

Of course, the easiest thing is to have a meal already finished and just needing to bake or reheat! Soup freezes wonderfully and whenever I make a pasta or veggie casserole, I like to make two at a time and freeze one. I've also used disposable aluminum bread pans and pot pie pans to freeze individual-sized versions, too.

I think the best thing you can do is have a plan. Make a weekly menu with your schedule in mind. For me, I have three young children and I utilize naptime as food prep time. I get all my ingredients chopped and ready to go so that once my oldest is home from school and our afternoons start getting wild, I just have to dump things in pans and whatnot.

Good quality frozen vegetables are a big time saver because they don't need to be washed and chopped. Learning to use the microwave for more than reheats is a great resource (Bittman did a whole exploration of this in the NYT--it's probably on his blog). The Crockpot is great for make-ahead carmelized onions and broth, and can "bake" a potato far FAR better than a microwave (wash, dry, poke w/fork, wrap in foil, cook on low for 6+ hours).

The best way to get faster though is to figure out the workflow of your favorite meals and figure out how stack it so that you really can do 2 things at once. If X is pre-prepped, Y is in the freezer, Z is in the Crockpot and you know you're going to start A, start B, finish A, and then do C the flow can really be streamlined.

Agreed with whitneyingram. Plans are good things. For breakfasts, I mix up a frittata in a casserole dish and bake it sometime early in the week when I've already got the oven on for something else. I try to prep everything Sunday night for the week's lunches and dinners, so that I can just pull out and cook (or pack, for lunch). This takes a few hours, but I prefer that to having the work spread throughout the week. I do have to write down the menus and put the ingredients together in the fridge, or I forget things...

I usually wash all my greens on sunday and stick them in containers in the fridge so I just have to chop and toss into soups, pastas, etc. Also, I have batches of tomato sauce and beans on hand in the freezer that defrost well in the microwave. Same goes with the pizza dough, which can be made into snacks, calzones and flatbreads!

Having an idea of what you are going to cook each night is key. I also clean and prep my greens on Sunday after I get home from the farmers market so that is one less thing I have to do. Also, as soon as you walk in the door, turn on the oven or if its pasta night, a pot of water goes on immediately. Once those are heating up, its one less thing I have to worry about.

A good tip for keeping fresh ginger on hand without it getting moldy: buy a large root and grate the whole thing into a small mason jar (with a lid) and cover it with just enough vodka to saturate. It will keep a long time, and when you want it, it's already grated. The vodka will cook off without adding flavor. I have found the pre-grated jars at the store often have corn syrup added...

These days, I tend to cook a couple of main dishes (casseroles, stir fries, pasta, etc.) and make a big salad and just stash them in the fridge for lunches and dinners all week. Years ago, when I used to cook dinner every night, the way I did it was to get it almost ready the night before; after we'd finished dinner, I would clean up, then prep and partially cook the next night's dinner so that I could come home and have it on the table in about 1/2 an hour. I've never liked "30 minute recipes" because they typically take longer than that and include all kinds of expensive processed ingredients. This way I can cook what I like without having to rush because I'm starving.

If you have a microwave, you can nuke potatoes a bit to keep them from browning - like par-cooking but less time and work. Putting them in a bowl of water all day will increase cooking time and ruin their texture because they will absorb the water.

Rice cooker + onions = a passable carmelized onion, with minimal (or no) stirring. Better if you keep the top of the rice cooker off.

Only things I prep beforehand I keep usually in my freezer. I keep chopped onion, celery, bell pepper and a ton of chopped green onion in there in plastic containers so I can shake some out as I cook (Depending what it is)
I make tons of fresh pesto in the summer and freeze it in individual containers os I can pop it out and toss with pasta for easy winter dinner.

A big one for me is meats. I buy big packs and pre section out what I need per meal and store everything in the freezer accordingly so I can just pull out a bag with 2 chicken breasts if need be or just enough ground meat for chili for 2.

My mom would peel/cut potatoes, carrots etc. ahead of time and store them in water to prevent browning.

Cooked diced potatoes, I believe, freezes pretty well.

I know this may sound horrible to non morning folk, but in the morning I prep veg or anything else that needs to be done in advance before I leave for work. It calms me, and makes the task of cooking when I get home less daunting.