One more point: use the delayed action to your advantage. First, I often wait for all my enemies to move first, unless I get a clear ranged shot right away.
Second, if you have an adjacent unit ready to take a swing, think about delaying his action if you can first move others into proximity to surround the enemy, and also if a different unit has the opportunity to stun him, break his shield or wear down his armor before you strike.
Also don’t be afraid to play on Easy for awhile until you get the mechanics down. Normal from the start is bloody unforgiving.