Currently, I do the following in order to improve my chess:
Play several (currently 9) correspondence chess games simultaneously on Chess.com.
Do tactics and puzzles regularly on Lichess.com and Chess.com.
Play occasionally against the computer (though not full strength) in rapid time controls (10|15).
I chose to play correspondence chess as it provides me a considerably good amount of time to think, and hence play to my best.
I also find that correspondence chess is easier to manage, as I don't have to be online throughout the game.
The thing is, correspondence chess moves so slowly, I feel that it would take me years to complete two dozen games (and hence improve my game).
My questions
So is it a good idea
to play faster time controls too (online),
or to increase the number of simultaneous correspondence chess games I play?
If the second course of action is better, how many games should I (optimally) play simultaneously to increase my performance?
If the first is better, what time control is the most suited to my need?
Note
Information that could be of some use to potential answerers.
I've heard that Blitz and Bullet chess aren't really good for learners.
My rating was between 1200 and 1300 in the rapid time control on Chess.com (before my data got erased).
My training (puzzles) reading online Lichess reached 1903 before falling to 1842, after which I've been inactive for quite a while.