Attention to modeling details such as structures and scenery is common. Simple layouts are generally situated on a table, although other methods are used, including doors. More permanent construction methods involve attaching benchwork framing to the walls of the room or building in which the layout is situated.
On a point to point layout, the train can increase the time it takes to get from A to B by going around a continuous loop a few times.
Single or double track or more, so more trains can run at the same time.
Intermediate stations, to distinguish between express trains which go straight through and local trains which stop briefly.
Branch lines, to add an excuse for more stations and different types of trains.
Use of multiple levels.
Arranging the continuous loop as a figure-of-8, possibly with one track going over the other instead of having tracks crossing on the same level.
Folding one loop of a figure-of-8 over the other loop to produce a looped-8, so as to reduce the amount of space needed while keeping a long continuous run.
Using one or more fiddle yards (US: staging tracks) to represent the rest of the railway system. A fiddle yard is regarded as off-scene; it may hold multiple complete trains, and may also be subject to direct human intervention (fiddling) to re-arrange trains,
Dog-bone arrangement of a continuous loop; the sides of an oval are squeezed together so it looks like a double-track section with a loop at each end where the trains turn around.
Rabbit warren; a continuous loop folded over itself several times with multiple levels and lots of tunnels for trains to pop in and out of - often a small layout with sharp curves and short trains.
There are three basic types of station, and sometimes combinations of these types:
Terminus or terminal station. As the name implies, all trains stop here, and then go back to where they came from.
Through station. Trains can go through this station; express trains don't stop, while local trains do stop briefly before continuing their journey.
Use of trains which can be driven from either end, e.g. Diesel Multiple Units.
The simplest possible station for passengers consists of just a platform beside the track, with no points (US: switches) or sidings. Both terminal and through stations can be as simple as this; a junction requires at least one point.