Medical first. What's the point in marginally failing CTC for example, being reinvited back in 6 months with no medical, then after all that time, realising you can't actually fly.
Prioritise. First establish that you can actually be permitted to fly commercially. Secondly, establish at which FTO you apply to.
The first thing I did before making any application was get the Class 1 medical - roughly this time last year. I'm re-applying at FTOs this summer and will have to get the medical re-validated but it's 1/3 of the original cost and I know that I'm medically fit to fly so haven't been wasting my time.