They try to make sense of relationships by developing theories and models. These theories are able to predict further behavior which can then be tested by experiments.
also u can go through LAKHMIR SINGH class 9 this is the best book which will help u a lot.
while going through chapters make sure u understand well nd then prepare notes for whatever u studied .
take ur regular tests which will show u what's u r level basically means they shows u how much learnt.
i hope they all will help u .
BEST OF LUCK.