How do stay in the lines easy when color in my art class it hard to sometimes stay in lines but i need stay in lines do anyone know how stay in lines easyier

It's quite simple. Here is a quick explanation:
1. if it is a picture then you should try to outlining the inside of the picture first (See attachment.) Then finish  lightly coloring the inside. 
2. You could color lightly instead of pressing down really hard, therefore it would be harder to see it outside the lines. 
3. Slow down a bit, you can take your time and make sure that when you color that the pen, marker, color pencil, crayon is staying within the line. Plus the picture will turn out better in the end if you dont rush through it. 

HOPE THIS HELPS.:)