Answer 1

Coder: reach Many Likes To Your Codes
Challenger: win 1000 challenge
Learner: Finish All Course
Contributor: Help Another User In Q&A
Influencer: Have 1k Followers

Answer 2

https://www.sololearn.com/discuss/361752/?ref=app

this thread has explanations on how things work in SoloLearn, including how to achieve increase in each skill.

Answer 3

Making many liked codes (Coder), doing many challenges (Challenger), get the certificate to all learn subjects (Learner), helping other users (Contributor) and having more followers (Influencer).
Like Jay Matthews say, it take time

Answer 4

just be patient it will happen as jay has said