The highest chance to get scouted for an mls academy is to play for another mls academy or a encl team, if your not on either of those teams just email the coach for a tryout
Playing in the MLSNext league, all games are captured on video and uploaded so that any clubs/scouts can watch them. I was invited to visit and tryout at a bunch of academies and ultimately Columbus felt like the right fit. I was scouted through video, scouts coming to watch my team's games, playing in events like the All-Star game at the Dallas Showcase during MLSNext Cup and local combines held by my club. Best advice would be to try and join an MLSnext club if you have one local.