Look like something is bugging you.
When someone makes eye contact with you, glare.
Smile creepily, and tell them that they are welcome to sit beside you. Be sure to deepen your voice.
When they continue to walk, look at them as if you are offended.
Be sure to try different faces
If you try this, you should never have anyone sit beside you on the school bus.
The creator of this guide has not included tools