Posted this elsewhere but it fits here too:
If you're at 125%, Diamond and wondering what to do next?
Help the newbies and wannabe Rambos to understand that the game is so much more satisfying and fun when you try to play stealth. Teach them all you've learned, all the little tricks.
A lot won't listen but that's ok, playing Solo queue with 2 randoms is almost like an extra difficulty level. I saw Macie doing it deliberately for the extra challenge, almost hoping his teammates got knocked so he got the challenge of trying to get them out on his own!
Don't ask "What's Next/What Now?"
Ask yourself what sort of challenges can I create for myself to get extra fun out of the game? Pistol only? No alerted enemies? Takedowns only?
You're only limited by your own imagination.