[Japo]

Strategically, one thing people usually do wrong (in my opinion) is enlisting as few soldiers as possible to get UFO raids done surgically. Myself, I fly 14 soldiers for every mission. There are other 6 at the base, basically as replacements, but if my base is attacked they'll help to defend (unless recovering from wonds). Defending a base with few soldiers is bad idea, far more so than in terror attacks, because you start so scattered and until you link your soldiers they're vulnerable and can be easily overwhelmed separately.

As for equipment, laser rifles are very good weapons, only second to heavy plasma--and you shouldn't equip all your soldiers with heavy plasma. Regarding armour, you're actually overdoing it. Equipping all your men with flying suits is a complete waste of resources. Equip only the best ones who can make the difference because of their accuracy, for the rest power suits is enough, and if there's someone who's worthless don't even waste a power suit and use him as cannon fodder up front--that is if you don't want to dismiss and hire a new one.

As for tactics, you must learn to be cautious. Don't try to advance as much as possible in each single turn making the most of TUs, rather play a greater number of shorter turns, move only from a safe position to another, never end a turn with your soldiers exposed. Think in terms of lines of sight for them and for the aliens. If you let them see you before you see them you'll be killed.