1.Don't let your shadow cross over into the other side of the splits screens space. If you do there will be an easy to notice line, that gives your split screen away.

2. If you do this outside, do it on a cloudless day. A cloud could pass beneath the sun and make the colors on one side of the screen darker, giving your shot away.

3. This must be planned out perfectly, in advance, set markers where you can walk without crossing into where the next screen splits.

4. If you're splitscreening yourself to make it look like there are two of you. Always look perfectly straight ahead to make eye contact with your "double". If eye contact isn't made, it makes the effect less real.

5. You seldom see a movie where it is one continuous shot for 2 minutes straight, so don't worry. You don't have to perfectly time all your actions for a full two minutes if thats how long your movie is. Get different shots from different angles or cut to just one of you for a few seconds, this will help you in making your interactions and film more real.