Leagues differ with respect to how they operate player tryouts. No matter what the procedure, however, it’s good practice to carefully study each player, and monitor his or her skillsets. Does the Little Leaguer catch pop-ups well? If so, you could be looking at one of your outfielders. Does the Little Leaguer field ground cleanly? If so, you may have found your shortstop. If there’s a running exercise at the tryout, and a boy or girl shows impressive speed, he or she could be your lead-off hitter.
Make sure you know your league’s player selection method, as well, to be prepared to build your team.