>>3927As for tips. Invest in a good set of tools and don't let anyone EVER borrow them because they never return them in good condition (if at all).
I do 99% of stuff with a set of metric+standard sockets, wrenches, screw drivers etc. You can get a good set in a nice suitcase style carrying case for not much money. The one I have now is a 154 piece set by Kobalt that I keep in the trunk at all times. Buy a good hammer (or two) to keep with it. Along with an impact wrench for sockets for stuff you can't get by hand and an inverter so you can power it from the car battery. Ditch the jack that came with the car and get a decent hand jack that doesn't take up much space. They sell a bunch that are pretty cheap and much better than the crap they give you when you buy the car.
Also learning how to solder and keeping a soldering iron or two with your tools is a good idea. Along with spare wire, electrical tape and leaded solder. I have two soldering irons one powered by AC/DC and another butane one powered by lighter fluid. They don't take up much room in the tool box and they come in handy often.
If you have room get a small air compressor so you can pump your tires back up in a pinch and don't have to ride the rim looking for a gas station with a working air compressor.
At home a decent work bench with a vice on it is always a good thing to have. Along with a grinder. I often times have to make tools by grinding down old wrenches to small sizes so they'll fit. Had to do that to pull a carb on a Kawasaki lawn mower engine just this week.
Also gauges. Always good to have gauges for checking air pressure and things like the current charge on your AC system. Pick them up as you need them. Keep an air gauge in your car at all times. Very helpful when you need to fill up a stranded motorist's tires because they were dumb and rode around at 5psi.
Buy a bunch of extra fuses and keep them in your car because eventually you're going to need one. Same goes for lights. Go ahead and buy spares for all your headlights and taillights. Gotten out of a few tickets because I could replace them quickly on the side of the road when I got stopped by the road pirates.
Same goes for oil and transmission fluid. Keep a quart or two in the trunk with the tools in case you ever need to top up. Spare air filter might be worth keeping around too but not as important.
Do the usual stuff and do it on time. Checking fluids, changing them, checking tires for wear, looking over everything a couple of times each season, greasing anything that requires it (CV joints, suspension etc). Speaking of that invest in a grease gun.
Hand wash the car bi-weekly so you see and touch everything. I've caught a lot of issues easy because my Dad taught me that when I was a kid.
If you car requires it invest in a OBD scanner. Saves a lot of headaches and you don't get ripped off by the shop.
If your state/area requires emission inspections establish friendship with the shop where you're taking it for that every year. I have mine done at the same place I buy tires. They will pass anything I bring in. Even if it requires hooking it up to another car. Since none of my post-1999 stuff is anywhere near legal.
In general if you do what you're supposed to be doing you'll catch major problems early or prevent them all together.