Time spent laying trackwork accurately is time well spent, and trackwork is usually laid onto a ‘sub base’ of thin sheet rubber, cork or similar material, this is partly to deaden sound, and partly to provide a softer base for the track which is either pinned or glued in place.
It is visually important when laying trackwork that straight track is actually straight, and that curved track is curved smoothly particularly at rail joints, using straight edges and curve templates can help considerably. In addition the top surface of the rail must be smooth and level, to give a realistic passage of rolling stock, and to ensure electrical contact for motive power.
There are many books, videos and articles written about track laying (some are listed below) but essentially, smooth curves, and smooth and flat rail top surfaces are critical in track laying.
The forum contains a useful article on the building of a single slip.
Figure 3. Showing track work laid on a 9mm birch ply foundation, and a 3mm cork layer, on which the paper Templot plan is glued.