1) Target Javier Mascherano - For me, the former Liverpool man, playing at centre-back, is a weak link for Barca. I want to see Wayne Rooney and Chicharito running at him as much as possible.
2) Don't crunch into tackles - We saw from Barca's disgraceful tactics in the semi-final that diving and simulation are as much a part of their game as pressing and close passing. United can't give the Hungarian ref excuses to award the opposition free-kick after free-kick and get his cards out. Some people think that United's lack of a typical Old Trafford hard man such as Roy Keane or Bryan Robson will hurt them. Actually, I think this is one occasion where it will be a positive.
3) Get the ball to Valencia - Playing in the centre of defence, Carles Puyol would get a nine or 10 in my ratings (below). At left-back, he's an iffy eight. If United can get the ball to Antonio Valencia regularly, he can torment Puyol. Rooney can exploit that by getting in behind him and the game can be won.
4) Play Park on Messi - Along with Valencia, Ji-Sung Park can be United's most important player. Yes, it's a shame to sacrifice his lung-bursting runs upfield by man-marking Messi, but in doing so he can knock the Argentinean out of his stride, disrupt the attacks which flow through him and win the ball for Michael Carrick to feed Valencia and Ryan Giggs.
5) Attack, attack, attack - Trying to soak up Barcelona's pressure and hit them on the counter would be suicidal. United must start with Rooney and Chicharito upfront and try to stretch the game straight away, being adventurous in attack and swarming to the man as Barca do so well whenever they lose the ball.