If you're a new player I have some advice. That is, try to set up choke points and let them come to you as running in with weak units will get you done in quickly, once you have some better soldiers you can be a little more aggressive.|
Snipers really come into their own with squad sight. Always choose that ahead of the other option unless you have several snipers.
Try to always be in full cover, also, there are, on every map points that set off the enemy so try not to head into the gloom too quickly.
Satellites are quite key early on, it's not always easy to juggle everything early on but try your best.
Hope all that is some help.
You are a factory of sadness.