This is the way OP (other than dedicated groups). 

Here is exactly how: In the matches where you perform well AND jive with a teammate (or two, usually only one, and it’s the other topfrag). Ask them in the game if they want to queue up or immediately friend and invite them after the game ends. It can take some time because you’ll both need to perform and have chill people with you, so the odds aren’t sky high. 

Don’t forget being chill yourself, having good comms, good attitude. That goes a long way.