Dear aspirant,

According to your question i would like to tell you that cracking neet and jee needs many days of preparation and strategy and there is very less chance to crack it but its still not impossible if we follow proper plan and strategy.

So, yes allen materials are very good for preparation but you should also practice sums from any other material or anywhere (not necessarily that you have to follow any other coaching material).

You should learn by heart the allen handbook as it's very effective for formula revising. You should target out easy kill topics which can be scored very easily in the exam then go for the tougher topics. Practice regular mock papers.

That would be enough for your good rank in these exams.