1) Get a trial lesson; you may not like it!
2) Visit a few schools. If you're in South Manchester, Barton is probably closest, but there are schools at Liverpool, Hawarden, Sleap, and probably a few places I haven't thought of. Visit them all, talk to instructors and students, and try to get a feel for how well they're run and how much they consider the student, and just which you'd feel happiest at. Don't necessarily go for the cheapest; it'll take you less time at a good school with a good instructor, so that's more important. It's well worth the time involved - I wish I'd done it.
3) Read as much as you can on here. Do a search; see which schools people speak well or badly of.
4) As mentioned before, make sure you can pass the medical. If there are any problems, you can probably sort them out, but the CAA has never heard the word "hurry", and you don't want to be waiting to go solo while they drag their heels.
5) Aptitude tests? Might be worth it if you ONLY want to fly if you can get your ATPL. If you want a PPL anyway, you'll almost definitely get it regardless; it just might take you longer if you don't have much natural aptitude.
Go for it and have fun!
