A few tips for those traditional track users (and probably others).
Test all track (new or used) to make sure that there is no shorting from the rail insulators.
When planning your layout use the widest radius curves that you can. O27 or O31 might be fine with the trains you have now, but in the future? Also, they will run better (and they can go faster!) with wider radius.
O27 curves can be found with O42, O54 and O72 radius, O curves with O42 and O72 (not sure about O54).
When laying out your track, mark where you will need fibre pins for blocks with a piece of masking tape – it’as a lot easier to do this than to remember after you screw the tracks down.
When screwing the tracks down, don’t overtighten and bend the ties, this could change the gauge slightly, or cause insulator shorts.
Avoid track joints when possible – single lengths equal to 3 straight tracks are available – use them when you can. Also, instead of using short filler pieces when needed, cut one of these longer pieces to the length of one or two tracks plus the filler piece.
Have fun building!