Clean and deoxidize your metal track rails using WD-40 sprayed onto a small section of very fine grade 3M scotchbrite pad. Use a fine rubbing motion. This will restore electrical conductivity to the rails. For a final treatment, use Pacer Rail Zip available in hobbyshops. This will retard oxidation for months.
When painting lexan and getting bored with factory colors, try using automotive base coat paints mixed with a flexible paint additive (the kind used on plastic bumpers). The flex agent prevents the paint from flaking and chipping on the track after an inevitable wall shot. Make sure the brands are compatible. (Slot HO offers no guarantee expressed or implied on this tip.)
Handling problems can be caused by a myriad of things. One possible cause is to look out for a dragging guide pin. Late model HO's are notorious for bottoming out in the early shallow lock and joiner track. File your guide pins down but be careful not to go too short as this can create de-slotting problems under heavy acceleration.
Remove the swiveling snap in plastic guide pin or blade from your'70's AFX cars and replace it with a snap in steel or aluminum one. The difference is astonishing!
For those of you who still race T-Jets, replace those old worn out stock tires with a set of new ones such as those sold on the aftermarket for independent rotating front ends. The traction and handling improvement is dramatic.
On a recenttrip to the hardware store, I happened upon the idea of replacing those old hardened TycoPro and Curvehugger tires with neoprene o-rings sold primarily for plumbing applications. They come in sizes to fit many rims and are low cost at about.40 each. Look for the "Jandorf" name They can even be stretched a bit for good fit.
Copper pickup shoes oxidize quickly and lose peak performance. They can be restored to their original electrical conductivity and lustre by soaking them in a solution of table salt and white vinegar for about a 1/2 hour. Then polish them with a fine metal polish like simichrome. Rinse in vinegar and set aside to dry. A drop of rail zip afterward is optional. (Great for your display cars).
HO parts and spares can get lost easily. Try storing your items in 35mm film containers. (I prefer the clear type that come with Fuji film).
You diehard hard body racers can benefit from going on a diet. Use a dremel tool and a grinding bit to remove excess weight from your plastic bodies. It will weaken the body marginally but drastically reduce weight which translates to a noticeable affect on handling.
Remember that "slide guides" and flags are intended for custom routed tracks and not plastic track. They can be ordered from your local raceway or dealer.
The latest HO drag racing rage appears to be using hollow rear axles. They are pricey though. Some guys are making their own by using some micro-diameter K&S brass tubing and sizing it to length using a tubing cutter. Outfit with your choice of gears and tires. I'm told it works well in Super G's. (it will eventually weaken though if you are using a high power armature.) Secure assemblies with Loctite 242.
When setting down plastic track for a permanent layout and you don't want to alter the track using the traditional screws and drill outs, try instead some 20 gauge nails, 1/2" long. They are manufactured by the Holland Manufacturing Co. and the nail heads are perfectly flat (no harm to tires and magnets). They will hold the track securely in place. A 3 oz. box sells for under a buck.