A tip one contractor passed on to me when caulking: use pieces of toilet paper to smooth it out after applying. You won't get your fingers gunked up, and toilet paper's cheap enough that you can use a bit to smooth off a few inches of caulk and throw the paper away.

Think I got through half a roll when sealing up a window frame a couple years back, looks great.

Watched dudes install a countertop. Apply caulk, one wipe, beautiful. After countertop installed I put in trim (it's a window to a patio) and need to caulk literally a straight fucking line six inches long. Caulk, wipe, looks like ass. Great work!

It's not that hard to learn. Just don't leave away the steps that you found too silly from the tutorial :)

Cutting the caulking tube tip is very important. If all the gaps are big, cut it so the hole is big. If they are small, cut it small. Cut it at an angle because you don't use it straight on. If it is water based, have a bucket filled with water and a couple drops of dish soap. Put one or more rags in the water depending on how much caulking you have to do. The water and soap are there so it won't stick to your hand and fingers as badly. Keep as clean as you can. I used to have to use cases of white lightning to caulk millwork and French doors on new McMansions several times a week. If it's not water based, use acetone or denatured alcohol depending. The tip cutting is still very important no mater what solvent or water is being used. Too small is better than too big.

Even worse: insulation sealing/foam

Put in my own dog door, I've used this stuff once before and thought I remembered how much comes out when you barely press. And then how much it expands.

That was a year ago and I swear sometimes it's bigger than it was before, still