Most schools like you to have the Air Law exam passed before you fly your first solo and possibly also Navigation before solo cross-country.
But, other than that, whichever order you want.
Personally, I go for the ones with the least actual flying element to them like Human Factors and Meteorology as some of it may not make sense until you've flown an aircraft (well, it didn't for me and I did my PPL exams before I started the flying!)
Cheers
Whirls