Not sure if this has been mentioned yet, but I have a few tricks (not sure how many of these would count as "hacks"):
1. Pre-cut/mince/julienne peppers, onions, shallots, celery, etc and measure out exactly amounts of each. Then wrap each measured portion in "Press 'n Seal" or a Ziplock freezer bag and write down the food and amount on the outside. Makes it a lot easier to add a portion of peppers or onions to a skillet in the morning before your coffee if you don't have to do any actual work in preparing them.
2. I like garlic, so I buy a lot of it, mince it as finely as I can and then put a saucepot of olive oil on the stove. When the oil is heated up just hot enough I add all of the garlic and wait until the garlic bits start to turn a yellow-orange, then remove the saucepot from heat and let it air-cool. It gives me what I call a cheater's version of roasted garlic, infuses the oil and if I store the garlic and oil together it'll last for a super long time. Now I can use just the garlic, the oil or both as a baste, drizzle or just to dip.
3. When buying cuts of beef, pork, poultry or fish I'll rub down the food with herbs, salt, pepper, oil or whatever then freeze the individual steaks/cuts/chops/fillets with the flavoring a still on them. That way I can take out one rosemary and cracked pepper steak, one Cajun tilapia fillet, one chipotle chicken breast and one BBQ pork chop from the freezer and have them all during the course of a few days.
4. I love to macerate fruit, particularly strawberries, and once the fruit has become nice and soft and is surrounded by its juices and sugar I'll divide up the juice. Freeze it in individual plastic containers and then you can get a shot of whatever juice you want in a morning smoothie sometime later.
5. Scrambled eggs are awesome and I eat them at least twice a week, so when I put the skillet on the stove I sprinkle in some herbs (usually rosemary, thyme or sage) in the bottom of the skillet, sometimes with a little bit of olive oil or bacon fat (from bacon that I've previously cooked and frozen separately). Now I can get started on preparing my eggs and when I can smell the aroma of the herbs warming up in the pan and releasing their oils I know that it's time to put the egg mixture in.
I guess they are sort of time hacks, and some good ones.
I've done meat items fresh from the store as you suggest in #s 1 & 3, but not with vegetables...yet.
#4 is a good one too,.
Baggies work for that, and also ice cube trays for smaller measured-out portions of stocks and even left over wine.
Once frozen, cubes can be dumped into larger freezer bags so there is no need to thaw out larger amounts, just keep plopping one or a few at a time as needed.
). Can't believe I've been doing it wrong all these years.