I Passed my ME IR Last week first time with AFT at Exeter. I don't consider myself at all to be above average or natural when it comes to picking up new skills.
My advice is pick a good school with a good solid track record, experienced, well qualified instructors and back seat as much as possible from day 1. The test is difficult but people do pass it first time and so don't spend too much time looking at pass rates on paper, get down to the schools and speak to the current students and instructors.
I passed in min hours (50 hr course) but I reckon I spent more like 85 -90 hours in the air over the 6 weeks. You pick so much up watching people making the same type of mistakes you will or have make.
Good luck to all.