UFO was definitely one of the hardest 1ccs for me and only PoDD beats it. It requires lots of practice and my hard and lunatic 1ccs of it are the only 1ccs I've done where I've gone beyond 100 attempts at a spellcard. There's a whole lot of stuff that can go wrong, especially with the UFO system. My initial attempts at High Sensitivity Pendulum were basically "OMG BOMB THAT NOW" but once I started getting close with 1ccs it ended up as "Ok, how quickly can I beat this this time :smug:". As for the UFO system, you'll get used to it to the point that you'll occasionally hit maximum lives (I've probably done so about 3 times, all at stage 4 Nue orb which drops a life if you "capture" its attack). Honestly, you need quite a bit of patience and skill to 1cc UFO but its quite a rewarding feeling, more so than most 1ccs imo. Also, in case you haven't seen it, there was this from the How to get to grips with Touhou thread:
There are quite a few spots where you'll have to make a choice between a red and a green UFO. The advantage of reds, of course, is that dying with bombs in stock doesn't hurt nearly as much, and you won't have to think about bombs at all after your stock runs out. However, bombs have the advantage of actually doing damage, as well as avoiding the power loss from dying. Really, it's up to you which to get. I've seen people have a lot of success with either or both - a common route to use is reds for the first four stages, and greens for the last two.
An important thing to mention is when to go after small UFOs. It can be tempting to grab them from near the top of the screen before they change colour to something less useful, but this is definitely not recommended if there's a decent amount of danmaku flying around; it's very easy to get blasted by a fairy from close range, and a death will definitely outweigh all the benefits you'd have gotten from grabbing the UFO. It's also worth saying that a UFO will delay its colour change if you are near it. This is useful if you want to grab it as it is, but if you're waiting for it to change colour, you're better off hanging back at a distance.
Other UFO tips include stuff like "It's usually worth bombing for a UFO" and "Planning out a route can be useful but reduces flexibility". Just keep at it and it should almost all come naturally.
Also, that part where you keep dying, you should examine it in some way and find a way around it. Either take a different route so you don't end up in that situation or find a spot to dodge through it. Looking over my 1cc, there was a point in that attack where I went quite off centre to dodge.
If you're tight for resources then you might be letting yourself use too many on early stages. I usually wouldn't let myself die before Kogasa's 2nd spellcard and would force myself to perfect stage 1 (including my UFO route). I made plenty of mistakes during initial runs. Mistakes that I repeated I figured out what caused them and avoided it (eg rushing for UFOs and then dying because the next pattern was streaming). Seriously though, practice and eventually you'll look back and think "I struggled with that before?". Good luck
