Here a little guide of what to do:
Turn one or two: skip.
Turn three: Magik, Electro (his ongoing ability isn't worrying for this deck (but If you can get rid of him, do it)) or Mister Fantastic (this one I recommend the least).
Turn four: Omega Red, another of cost-3 or if you play Electro: Iron Man, Blue Marvel Gilgamesh (important to know that you should play him after Blue Marvel) or Klaw.
Turn five: Iron Man, Blue Marvel, Gilgamesh, Klaw or if you play Electro: The Living Tribunal.
Turn six: The Living Tribunal oooooor if you play Electro: Onslaught, Spectrum or Galactus.
And if you play Magik there is a turn seven, so: Onslaught, Spectrum or Galactus (if you play him make sure of don't play any cards in the location where you will play him), Onslaught and Spectrum both serve to enhance The Living Tribunal and split more power among locations... But wait! There's more! I think you know what: and if you play Electro also of Magik you can do even more power for The Living Tribunal, here's and example: turn five I play The Living Tribunal, turn six I play Onslaught and in turn seven I play Spectrum or Gilgamesh, See?
One last thing: I recommend to play Magik and Electro (really great combo).
One very last thing: if you don't have Gilgamesh you can replace him for Ronan, Devil Dinosaur or DarkHawk (you really can change any card (except for the essentials) of the deck for other cards that give, have or obtain power (a lot of power would be the best) ).
And one super mega last thing!: I really recommend to play Galactus.