YouTube is awesome for car repair. Whatever you need, there's likely a video on it for your make and year of vehicle. Your owner's manual can sometimes be very useful too.

Everything I mentioned I'm sure has a video on the subject. Now I'm not inclined to watch videos when I don't have to, so besides car repair, things like Army Field manuals are freely available and have a lot of great survival information.

For cooking, all you have to do initially is be able to follow a recipe -- that's all a lot of people manage anyways. Trick is knowing what's a good recipe and what isn't without experience, and the solution there is to rely on other people rating the recipes for you. I think AllRecipes.com is really handy in that the popular recipes have thousands of reviews. You rely on their experience until you have your own.

Fermenting and preserving is even easier. There's only so many methods: storing in oil/fat or honey, smoking, lactobacillus ferment (just submerge food in a 4% brine basically), picking (similar but you add the acid instead of having the bacteria do it), drying (pretty self explanatory), canning, and of course yeast ferments are handy to make booze and breads. There's a ton of articles and videos out there on each.

Gardening and fighting, I think the best way to learn is just to do. Spar with a friend, throw some seeds in soil. Go from there. You can always supplement your knowledge with other sources, but all this stuff really, until you do it, you just know the theory of something.

How to reason is trickier. I think logic puzzles and programming helped me here. The Socratic method, the scientific method are handy too.