Get tuition help if you can afford it (though some students
benefit more from tuition than others; and this is a case-by-case
basis not only dependent on the individual student, but on the
individual tutor involved as well). The quality of your 'O' level
grades will make a huge difference to the pathways available
for the rest of your life.
(The statement above remains true, even though of course,
it's possible you can fail your 'O' levels but still succeed
in life and become a millionaire through hard work and personal
ingenuity).
Even though my personal take is that (at least for
Chemistry), tuition is more necessary at 'A' levels compared
to 'O' levels, (meaning that as previously mentioned by
SummerHill, at 'O' levels you can mostly self-prepare by doing the
TYS, while in contrast 'A' level Chem is getting
increasingly tougher and the TYS no longer suffices), but it's
really a difference of function for tuition at these
different levels (eg. 'O' level Chem tuition more for
drilling guidance, while 'A' level Chem tuition is more
for understanding guidance).
Anyways, as an FYI :
Both Eagle (Mr Tan) and WenShih (Mr Wee) offer Mathematics
tuition (both at 'O' and 'A' levels).
Eagle (Mr Tan) offers Physics tuition (both at 'O' and 'A'
levels).
DarknessHacker is currently busy with his NS (correct?), but
offers Biology tuition (both at 'O' and 'A' levels) when he is
available.
ChemGuide (Mr Chong) offers Chemistry tuition (both at 'O' and
'A' levels).
As for myself, I offer 'A' level H2 Chemistry tuition
only (and not at 'O' levels).