I'd first suggest getting Jecht Shot for Tidus because that's a great way to score, especially because it eliminates several defenders and is hard to save. Get a good defender, such as Ropp, and get Biggs and Wedge on your team. On lower levels, Wedge is a really good attacker. For me, he usually does even more goals than Tidus. Brother is also a good player. Get a good goalie (I had Miyu) and have him/her learn the Super Goalie ability. Play several games and let your players develop, and you'll also learn some good tactics while playing.