As Fishmanoz said, don't use 1st radius at all, and try to avoid 2nd. The gentler the curves the better really. Remember you can use flexitrack instead of set curve pieces, which can also make your line look much better visually. When buying track stick
to recognisable brands such as Hornby and Peco, once its all down replacing dodgy track can be a hassle.
We're not really supposed to talk about other brands here, but some people have reported problems with Hornby points, so do explore your options
in that area. Another company also makes Electrofrog points which eliminate the problem of locos stalling, although they can be more awkward to wire up. You might want to look into that too.
Don't put a curve right next to a point (unless its a gentle
one), or use inclines unless you have a *Lot* of space. Also make sure your track (in particular points) is layed absolutely flat.