When you recognize the player then you can recognize their stats, its that simple.
Whether its online or live but you have to know the game/poker form you're playing well enough to accurately judge your play and someone else's. You can't say, you should play" x way" and your online chart look like "\" or your live bankroll
is busted, lol that's not being accurate.
You will be able to recognize who the successful grinders are by how many hours you see them in the casino and how often and whether they're taking chips back to the cage or someone you see all the time who is rebuying and rebuying or who the "just there for fun" and want a place to hang out at after work folks are after awhile.