Important things to look at are sportsbook lines and player stats/matchups. I haven't played much soccer, but it's always a great way to get interested in a new sport.
But for instance in baseball, when picking a pitcher you generally choose the largest favorite with the best strikeout prop. Also look at opposing team's implied run total, pitcher's game logs and try to pick the best choice salary wise. Then for hitters you generally choose the best $/pt values to fill out your roster alongside elite players in great matchups. The hitters usually come from highest team total games and players towards top of batting order. Or anyone who plays in colorado cause those games get a little nutty