Police Training involves two components:
1) Physical Training (Drill, self-defense, swimming,
arm-tactics, IPPT, etc)
2) Law stuff
If you're physically fit when you were in school (e.g. at least
a Bronze in NAPFA/IPPT), then the physical part would be a
breeze.
Law can be tuff for those who are weak in English but don't
worry, somehow, you'll pass :p
Having a positive attitude helps too because the things that
make your life in HTA fun or hellish depends a lot on your
squad-mates.
Need a bit of luck too on the kind of trainers you'll be
getting. In general, most trainers are bastards at the beginning
(1st month) but they'll slowly become friendly towards the end.
Most of us don't want to have a bad reputation because words spread
easily in SPF. Even after 6 years later, people can still recognise
me as an FI when I go for reservist.
In summary, just go there with an open and positive mindset.
It's bad enough that we have to do NS... hence, might as well make
the best of it while you're serving :)