You can get a good order of missions from Joana's Starcraft 2 brutal campaign missions guide.
Sometimes it is important to pick the right missions in a specific order so that the game is easy to beat on hard and brutal difficulty. Starcraft 2's single player campaign missions are not done in a linear fashion, instead the game evolves from completing previous missions and you will have different mission options to pick from as you progress.
Joana's 1-60 Classic WoW Horde & Alliance Speed Leveling Guides.