How to get into one of the teams in Agar.io?

I am currently at level 35 and whenever I play Agar.io there are always preexisting teams in the arena.

When I was playing today, a new cell emerged which was at a level > 80 ( and was way smaller than me in mass ) and out of nowhere a very big cell started giving mass to that small cell so that it could eat me! Why don't the big guys give me mass as well?

Due to these guys, it is almost impossible to reach #1 on the Leaderboard!

Possibly because a few friends are playing together and have chosen unique nicknames. Then they can identify their friends and feed them and win together. If you ever get a chance to call a friend with a computer and play together on the same server, or if a few friends can use a few computers at school, or the public library or internet cafe, you can do the same.