It's different every time, since I keep trying different stuff. I haven't been lucky enough to be able to get my hands on multiple Ion weapons (except my last run, but I was forced to neglect some defensive capabilities, and ran into like two shops that would have been better off selling me socks leaving me with little in the way of augmentations as well), but other than that I've been able to attempt a wide variety of methods. I don't want to attribute all my losing to bad luck since I can usually see where I screwed up, but things have just not been falling into place for me.
The thing about this game is that bad luck doesn't make the game hard, it makes it impossible.
If you keep encountering enemies with missiles, and no shops sell any decent weapons, you ARE fucked.
You know, about a year ago I tried to see what percentage of normal runs I could win as the Kestral.
It was WELL over 50%. And I think I could have gotten it higher with enough dedication. Seriously, the key to FTL is that its only greatly luck based when you're losing. If you're ahead of the curve you have ways of managing. So playing with a solid, versatile ship there should only be like 5% of the runs where the game just said "fuck you".
I think I've just had the single most unlucky FTL game of my entire life. It was Slug C on hard. I sold everything on my ship (which isn't saying much, Slug C's useful assets are systems not equpiment) for a Flak 2 in sector 2. What happens after that, do you think?
Everything hit my weapons bay. Every. Single. Thing. Not literally of course, but I think more than half the missiles fired at me past that point hit the weapons bay, it was truly ridiculous. It got to the point where I could call it, not because I actually had any predictive powers but because my ship was fucking cursed.
For example, this. I was playing as Slug C, which has only a chain laser. I felt I needed to upgrade my weapons and the only available option was a flak 2 that I couldn't power, so I had to sell everything to get it. I was putting myself in a position where luck could ruin me, because I felt it was my best option. This, in turn, was because I was playing a ship that needed hacking to kill a two shield layer ship, which is a bad place to be in.
The Kestral, on the other hand, can reliably kill 3 shield layer ships from the start. With a second laser or beam weapon of any kind it can kill 4 shield layer ships. There is no excuse to do badly with that layout in the first or second sectors, which means you have two freebie sectors to prepare yourself to face the rest of the game.