Keeping your side
In Nepal you drive on the LEFT. Driving on the right-hand side is an offence and is one of the situations in which the traffic police can act against you on the spot.
Stay in one lane and hold it. Weaving between lanes to gain a few metres gives the drivers around you nothing to predict, and it is the manoeuvre most often behind a collision on a straight road.
Slower vehicles keep left; the right side is for overtaking and for turning right. On a road with a centre line, treat that line as a wall unless you are overtaking and can see far enough to complete it.
Before any change of lane: mirror, signal, and a glance over your shoulder for the space the mirror does not show.