it all depends and varies from person to person. i have given GAT general few years back and my score was 74 and 76. My strength was maths and analytical reasoning and i scored 29/30 and 30/30 in maths as it was of level of 5 or 8 class and not much difficult. in analytical reasoning my scores were 36/40 both times. I prepared for analytical reasoning from discrete mathematics book I then borrowed from some friend and did not remember its name. I failed to score average in English.

my technique was to do maths first as it was the easiest part and i was able to solve 30 questions in less then 10 mins.
then i tried analytical reasoning and for it I wrote each statement in mathematical form and then used deduction to get result. even-though I wasted my time in this, but it showed in result also.

So my suggestion is that one should try to solve those parts which he is more confident in or everyone should try maths first but should not give more than a minute to a question and if unable to do it, then should make a precise guess and move forward.
for analytical reasoning, there are a couple of chapters/topics in discrete mathematics which are very simply and helps alot, and i would suggest everyone to spend a couple of hours on it.