Earn additional energy - Energy is an essential part of Marvel: Avengers Alliance, especially since battles cost you several units. You can wait for it to replenish on its own, or you can gift and receive energy from Facebook friends to keep on chugging. You can gift energy between friends multiple times a day up to 50, all but eliminating the need to wait for your stores to replenish.
Hoard silver and gold - Silver and gold are the premium currencies you can use in-game to buy additional items or features. Of course, you could just purchase this currency -- but you can earn free gold with each level up or by completing several in-game tasks. Complete the 4th star mastery per mission for additional gold as well.
Earn S.H.I.E.L.D. points - These points are an invaluable resource for research, item purchases, and training. They replenish quite slowly, like the rest of the premium currency, but instead you could travel to the maps that your friends create in order to pick up more points. Additionally, your friends can gift you points and vice versa, for when you aren't happening upon the points at random so often and need a boost.
Pick up as many Command Points (CP) as possible - CP are required if you want to recruit new heroes, and usually they drop after completing specific missions, bu opt to complete each 5th star mastery per mission and you'll be on your to a hefty cache of points in no time.
Unlock "normal" missions by completing prerequisites - Usually, you'll continue along in order to unlock new missions, but sometimes you'll need to meet certain conditions in order to pass. Make sure you're meeting requirements before advancing to make sure you're on track.
Unlock "premium" missions by making special purchases - Some premium missions require you to buy a specific Hero, so go ahead and put the cash down when necessary. More often than not, you'll be greeted wth a cavalcade of nicer items.
Choose the best heroes at your disposal: There's a vast assortment of heroes in Marvel Avengers Alliance, but not all heroes are created equal. Before you go buying up the heroes all willy nilly, consider picks that have low-CP cost attacks, or support stats. For example, Iron Fist offers cheap healing abilities and acts as a well-rounded brawler as well. Iron Man, for example, is a free character and one of the best ones in the game. Usefulness is not rated in CP, so take the time to evaluate the heroes you're adding to your team before you start spending points.
Download Marvel: Avengers Alliance for Android.