1. Wear eye protection:
a) Every time you use a power tool.
b) Every time you use a hammer.
c) Every time you're using a tap or other brittle, hardened tool. They can, and do, shatter.
d) Every time you're under a vehicle. Falling dirt and debris can go anywhere.
e) Any time you're in the shop and you think that there might be some small chance that something could break, spin off, or fall and end up in your face.
2. Ear protection is a good idea as well. Ever used an air chisel or air hammer?
3. Filling the void in a set of diagonal cutters with silicone will keep small bits of wire or zip ties from being flung across your truck or garage. Split the silicone with a razor once it sets.
4. Grinding the face of a pair of diagonal cutters flush will allow you to remove welded-on studs and trim wire ties without any tag ends.
5. Paint or mark with colored tape the stops on your jack stands with different colors or with numbers so that you can easily level your truck once you jack it up.
6. Add about two feet of pipe insulation to the bottom of your jack handle. It will prevent the handle from denting the rockers or roll pan and it costs less then $2.
7. To start a nut at an awkward angle, put a loop of tape, sticky side out, in the socket. It will stay in place until you get it threaded.
8. If you've got even less room to work with, use a ratcheting wrench and use tape to secure the nut. It will come unstuck once it gets threaded on.
9. When you're taking something apart, take photos of the process. Digital cameras are cheap, and digital photos are free, so when it comes time to put your truck back together you'll know what it looked like when you started so you don't end up with "extra parts".
10. Along the same lines, bag all of your fasteners in zip-closed sandwich bags and label them with a permanent marker. If you've got the photos and all the fasteners, you'll have a much easier time re-assembling your truck, even if it's several months later.
11. Before using a hole saw to cut a large-diameter hole, cut a small hole near the outer edge for the metal chips to fall through, it will speed up the cutting.
12. Drilling two extra holes close to the pilot hole will also allow you to grip the piece and remove it from the hole saw once your cut is finished.
13. Snap-On and Blue Point both have magnetic can/bottle holders that will stick to your toolbox and hold a can of WD-40 or PB Blaster at the ready. Or, use it on the dash or door panel of your beater old truck to give you a place to hold your drink. Pop it off at a show and your old interior looks stock.
14. A 12-point socket will fit onto the square shaft of a tap so you can chase threads easier than with the T-handle.
15. Lay a large piece of cardboard, or better yet, carpet, underneath your truck if you're working under the hood. Any dropped tools or parts can be retrieved by sliding the cardboard or carpet out, rather than climbing underneath. Carpet will also help keep those dropped parts from rolling away.
16. Carry a spare serpentine belt! This is especially important if your truck has an aftermarket supercharger with an odd-sized belt and it decides to spit three of the eight ribs, wrapping them around the harmonic balancer so badly that you have to cut them off with your pocketknife. It's much cheaper than a tow. Guess how we know about this one?
Two ways to spot where a misfire is happening:
17. Use a spray bottle to wet the exhaust manifold near each exhaust port. The firing cylinders will quickly vaporize the water.
18. Clip a timing light to the spark plug wire to help diagnose if the problem is a bad wire or distributor terminal. The dead plug wire won't fire the timing light.
19. New trucks don't have long plug wires, but if your older truck has a misfire coming from the plug wire arcing to a short, you can find it quickly by just turning off the lights in the garage and running the engine in the dark, making the arc easy to spot.
20. Use anti-seize compound on all of your stainless steel fasteners and any time different types of metal are threaded together, like spark plugs into aluminum heads.