Take the tips up above, as they were my reference. Below are additional tips for my Ironman mode run through.
-My 6 squads were sniper, 2x Heavies with double grenade and Rocket (One anti robot), 2 support, one medic one sentinel, one assualt with shottie (yes over the plasma rifle, Crit damge on shottie is deadly, my assault had the 2nd most kills and was close to my double tap sniper).
-I went with tutorial in North America, the tutorial will get you a veteran sooner than a non-tutorial, not to mention non-tutorial you have 4 guys that may die the 1st mission, whereas the tutorial gives you one and a few missions before the actual non-tutorial mission. The tutorial also give you a 2nd satellite for free, non-tutorial you have to pay for it.
-I had the DLC, it is nice by doing the first mission you get the dlc character, and that gave me my two heavies for the game (one tutorial, one dlc). the DLC character I think has one more hit point and a little better accuracy, so that is nice.
-Having the DLC makes the council give you the missions (I did the 1st mission only then rejected the next one), rejecting it until you are powerful enough does not increase panic or count against you, so it may frequently pop up, but it can save you one or two extra missions over a couple of months until you are ready. So I didn't do one escort mission after the DLC mission.
-make no mistake the 2nd DLC missions taken early can be a death trap, regardless of Igor's above post.
-I didn't build a laboratory or a workshop. two power plants, one steam plant, one Elerium generator should suffice for power. I had two satellite nexus and two uplinks in a square, i.e. 2 1st level, 2 2nd floor. The Foundry came later, essential for unlimited alien nades, ammo conservation, improved med kits, pistol perks. Negative on any Shiv items.
-Research the items that matter, just because something is 4 days, and something is 10, shouldn't dictate your selection. I wanted the titan armor as soon as possible, instead of doing autopsy which only a few add value, I would go for the meat and potatoes research.
-Stage your satellites and always have one to launch. A few times I had a 5 bar panic country ready to leave and I would coo them with a satellite launch. Even though that country might have only contributed 50 dollars, it was worth it considering the "All in Bonus"
-The All in Bonus is one of your first country bonuses to focus on. However do not risk losing other countries to obtain it.
-Balance spending in key areas, some of the OTS perks are helpful, however aside from the squad size and recovery time, the others are fluff on a low budget.
-I used the same 6 people, the quicker they level the better killers they become, I had no interest in balancing and rotating. If someone takes damage, swing him out from the front. The reason you want better armor is unless the damage exceeds the armor they don't need to recover.
-In the beginning I disregarded the grenade and got nano-fabric (+2 HP) for everyone, it was the only way for them to survive a shot from sectoids.
-When you have the option of abductions, go for Engineers or money (after considering panic levels). Engineers reduce the money spent on items you buy, and at some point some things are locked until you exceed the number of engineers. After I was set for engineers I would take the money if feasible.
-When you reach the point in the story for the Hyperwave beacon, do not build it, continue playing and doing research. It took about 6 months before they introduced the Sectopod, but by then I had Titan Armor and Plasma weapons. I eventually built the Psi Lab, sent one soldier, and had that ready. When I did build the Hyperwave, it was less than a month until it found the ship, cleared it, built the next facility, had the armor researched and purchased. So it was a quick clean finish.
-On typical combat keep your team close, yes the nades are annoying but actually when a nade hits it does 5 damage to both members. When they shoot at you it can be 6+ damage easy, which means it might be R&R time for your soldier. If your team is too far spread apart you will falter on defense. Often times when I did spot a group, through various tactics I could clean them up before they even had a turn to attack. In my game I killed 371 aliens, 186 of which were terminated in one shot.
-Consider attacking with the sniper first, if there are too many, consider attacking with heavies and support, then sniper and assault last (namely because of run and gun).
-Heavies with the double fire skill help, they might miss once, but when you are about the 50% chance to hit, sometimes that 2nd shot helps.
-Use explosives liberally, taking out a wall may lose you a turn of attack, but it can open a window for a sniper bullet or team attack. On a couple tough missions rocketing the wall helped turn CQC to long range firing.
-Know about how many enemies you are up against, it helps you manage your team and tactics. If I know its 23 enemies and I am fighting floaters, I may not want to use a nade when there may be 20 other guys more deserving.
When someone does die or you make a grave tactical error do use the dashboard method. Every now and then I would fire a rocket and it would go wide left, that can be the difference between cleaning house or carrying corpses. Purchase a memory stick, and copy your game, you never know when you may not recover from a mistake.