I've played with Porto previously, you should be able to walk the league every season, with your only real challenge being Benfica and maybe Sporting CP.
Your first two signings really should be a right back and a Goalkeeper, get rid of the deadwood in the team and don't forget to add sell on clauses.
A 4-3-3 with control mentality against weaker teams and counter against strong teams is probably the best for the team, play Fernando as an defensive midfielder on defend duty, and Moutinho as an advanced playermaker support in centre midfield with Souza as a box to box. Play Hulk on the right wing with the inside forward on attack duty (He will destroy everyone playing there)
The league doesn't have the best prize money or sponsorship, so doing well in European competitions and buying youngsters, developing and then selling them on for profit is a good way to make up for this and as there are no restrictions on foreign players in the league getting Brazilian and Argentinian youngsters is a doddle (just load the leagues at the start).