I don't think there is a 'best tactic'
each tactic is dependant on the players you have and the positions that they can play, besides which, a tactic is only part of being a manager - there are so many other things to consider when it comes to 'winning games'.
What have your staff told you would be the best tactic for your squad? Find out that then look for a downloadable tactic/create one of your own that suits the players you have got...