Please how do I know if some one is online to compete with him/her online so that it will not go waiting?

Answer 1

The online status of other users is unfortunately still not an available feature on Sololearn.

Answer 2

Check people's profile, You may find the time a competition was over, sometimes you see now, which means one of the opponents or both are online
OR
Check the leaderboard the top 10 globally or locally are mostly active throughout the day

Answer 3

Ok, we hope in the near future it is going to be shown