Here's a bit of advise that works for me, if you don't mind:
Did you use tanks? They can be lifesavers during the early game (literally.) They can take multiple hits and can find aliens that your soldiers can snipe from a distance.
In my opinion, you should start laying groundwork for a second base as soon as possible, usually sometime during the second month, with a third base coming a month or two after that. Three bases that are placed correctly and stocked with soldiers and crafts can get you through the game, so you can slow it down on making other bases after that, or just make future bases for radar or production purposes (though if you have the money to build up you're bases beyond that, why not?) Personally, I like having a lot of bases when I can afford it, but it's not really necessary.
Also, if you're going Ironman, pick and choose your battles. Terror missions and MiB are generally a one-way ticket to a full squad wipeout early on if you're on Ironman. Not responding to terror missions is a massive loss of points, so just show up, gun a few near your ship and get out so your soldiers will see another day until you have the guns to get through it more easily.
