Get a remote controlled laser level so that you don't have to be near the level to turn it on. This way you can set up the level in a safe place away from anyone who might bump it. Bumping any level could throw off the measurements. You can also get a more elaborate laser level that will make a sound when the equipment is jostled, so you know to check and adjust it if necessary.
Use a rotating laser level if you need to use the same level location in various parts of the room. An example of this is when you are installing a chair rail round the room. Set up a rotating level in one place and simply rotate it to the wall you are working on. This way you know that all walls are marked the same.
Be careful when using a laser level. The laser is dangerous to the eyes. Make sure that children don't play with the level, and use special laser protective glasses just in case when you use them.
Aim the laser near a corner and the unit will project the laser on both walls. This is helpful when you need to install something such as cabinets around the room. You can also aim it down a long wall to use as a substitute for a chalk snap line.