How long does it take to cook meats?

I think experience over time tells you for a particular heat, and thickness. Experience also generally includes knowing your equipment. Your oven is not the same as your friends, or the same as your mothers. To start out, for poultry you should utilize an instant read thermometer to be safe. Beef, is done (and while this doesn't work on all cuts) if you place the tip of your thumb touching the tip of your index finger you can feel the muscle below your thumb and that is considered rare by feel. Some claim as you move up your fingers, to finally the pinky, the pinky is a well. I think that's ok as a general rule, but there's more to cooking a steak than feeling one section of it and calling it, particularly when near the bones the temperature can be quite a bit different.

Seafood, varies based on what you are cooking. Shrimp are done just as they become opaque. Fish, depending on your desired doneness, should just be firm. If you are working with particularly thick cuts of fish, well, feel probably won't help you much, you either need to take a read of temp, or try try again and get it down pat.

We're talking grilling?

Adjust temperature based on the type and thickness of the protein.

Determine red meat doneness by touch (usually).  When red meat almost pushes back, it's rare; just pushes back it's medium rare; starts to firm up, it's medium; more and it's overcooked.  For medium-well (ugh), cook to medium and allow a little additional carry over.

Fowl by shrinkage and touch (mostly should be just past the push-back stage and starting into firm.

Fish by appearance (very thin translucent band in the center, and touch (just pushes back).

Meat on the bone -- ribs, chops, chicken thighs, etc., also look for shrinkage around the bone.

In other words, use all the visual and tactile information you can.  And don't forget your smeller.

BDL

These days semi-decent steaks are not expensive, and while there is certainly variation among cuts and qualities, you can learn this experimentally by sticking to one cheap cut.

Grab a bunch of cheap, medium-thick steaks and some friends. Get a big cast-iron pan or grill. Dry with paper towels and then season all the steaks identically a little in advance.

Throw all the steaks on the pan at very high heat. Immediately poke with your finger. This is what raw feels like. Keep poking occasionally: it's still raw.

Flip all the steaks at 2 minutes. Notice how the cooked side feels firmer, but behind the firm you can still feel raw. Keep poking and prodding until you see what I mean.

After 2 more minutes, remove one steak and flip the rest. Have a big, warm plate and and a big dome to cover the steaks while they rest, and put this over the one removed.

Remove the next 1 minute later, still poking and prodding often. Another 1 minute after that, then flip the rest. Keep going until all are removed.

After all the steak have been removed and have rested at least 7 minutes and no more than 15 (unless you've got a heck of a lot of steaks, they'll be done at the same time), cut every steak straight across the middle and look.

You should see everything from blue to well in neat progression.

Once you get the hang of it, you'll know by feel when a steak is done to this or that level. It doesn't take long, and don't be afraid to experiment. But be sure to let them rest: un-rested steak will appear very different to what it looks like properly rested.

Once you know what cooked red meats feel like -- and this includes not only beef but also lamb, mutton, and many cuts of pork -- you can begin to work on chicken. Chicken is harder, for a large number of reasons, but it can be done.

Start with roast chicken, which is in many respects the hardest but is also the purest. Besides, roast chicken is an excellent dish to work on at home, because it's an essential culinary technique few budding restaurant cooks have time to perfect, and because it produces such fabulous leftovers for your breakfast, lunch, and after-shift snacking.

When a chicken is done to perfection, in the old days they'd say it sang: la poule chante. Only a rather good chicken, very fresh, beautifully cooked will still do this. But when you've heard it, you'll never forget: a very good chicken roasted at medium-high heat will hiss and crackle in a distinctive fashion to tell you it's ready.

A cheap chicken, however, will never do this, because it's full of water and the bones aren't retaining heat the right way because the chicken is too young. So what you do is, you get an ovenproof probe thermometer, and you shove it in the thick part of the leg, and you poke the same part of the other leg every 5-10 degrees from 130 all the way up to 165, when you pull the chicken and keep poking and prodding for 10 minutes (with the chicken under a dome) until it's ready.

Once you can feel it, almost exclusively by texture, but also by sound and smell, everything else becomes superfluous. You find yourself using a thermometer and thinking, "no way that's done, I don't care what the temperature says," or the opposite. Sometimes you make a mistake, but pretty soon you won't, because you will know by feel. And then you'll be responding to this question instead of asking it.

Believe me, this is easier than it sounds. But start with a steak party: it helps immensely to speed you on your way.

Another useful tool is your good friend google.  I recently moved and found a surprisingly expensive gas grill left in the back yard of my new house.  I've never cooked with a gas grill before so I googled for instructions, something along the lines of "salmon steak" "gas grill" "cooking times".

Whether it's gas or charcoal, lots of folks have written guides as to placement, intensity, and timing.  I would use that as a starting point and experiment from there.  Also, don't be afraid of taking something off and slicing into it to check.