Tactics (EU2012)

Leap frog your way forward on maps while also rotating through your squad's first move before deciding to perform a second move.
Overwatch, or fire if you encounter something along the way.
This helps you maintain battlefield awareness including map size, squad spacing, and flank openings.

It will also help make sure you have someone with a move left to take action should you encounter aliens.

Save putting your soldiers on overwatch until the end of the turn. This tactic is important for 2 reasons. 1. Aliens get a free move when they are seen and if the alien moves into view of a soldier that has already been put on overwatch they cannot use that turn to fire. You have to rely on them having a reaction shot during the alien's turn. 2. If you want to move them somewhere else you can't because they are locked once on overwatch.