@Osmose if the recipe says 1 clove of garlic, use five. Freeze coffee in an ice cube tray if you want iced coffee that stays coffee as the ice melts. Buy a $5 milk spinner thing, it also works wonders for dressings, cocktails, and airating single glasses of wine. Buy squirt bottles. Buy literally any kind of sharpening stones and use them.

@Osmose
chopped walnuts fried in butter make an exceptionally nice "meaty" vegetarian soup base
Kitchen funnels exist -- very useful for filling jars, etc.
You can make so-called "Sriracha Aioli" by mixing Sriracha into mayonnaise.
Add a generous quantity of instant coffee to your chocolate cake, icing, or brownie recipe -- espresso is even better, if you have it.
Bigger salt crystals taste saltier for the same amount of salt, and Maldon or similar is perfect for pasta or etc.

@Osmose use stock paste concentrate "better than bullion" any time you put water or a can of liquid in a recipe

Never wash out pan drippings... make a roux and a sauce or gravy

Cook peeled pearl onions into red sauce for a meatball alternative

Any recipe involving sealed tortillas can be easily frozen

tiny whisks are also pretty useful

@Osmose you can put olive oil or your oil of choice into a little spray bottle
a little bit of sesame oil makes cheap ramen taste deluxe
you can get a mix of frozen chopped onion, pepper, celery and parsley at the dollar store and it makes everything better
to make them last longer, use wooden or plastic utensils on nonstick cookware, clean with the soft side of the sponge
garlic chili paste adds a Sriracha kind of kick but without sugar so it doesn't burn if you cook it

@Osmose white sauce/bechamel can be made into almost anything
if you keep them in the dark spices and herbs last much longer
tomato paste in a tube is handy when you only need a little instead of a whole can
citrus juice adds sour, citrus ZEST adds flavor
if you don't have buttermilk for a recipe add a little vinegar or lemon juice to milk, works just fine