Hey Jahan.

For filling the preferences for CLAT, you should first make a list of your preferences in your mind considering all the factors which you consider as important. These factors can be university reputation, faculty, studies, scope after graduation, infrastructure, hostel facility etc. 

You will then have to fill all the preferences. Do not leave any place vacant. Because who knows you might get a good college. Leave no stone unturned. 

All the best.

Dear JAHAN

greetings,

Yes, you call select all the colleges while filling for CLAT but do keep in mind to make a preference list first, and fill the list according to your preferences so that if you didn't get the 1 choice then you can have more probability of getting the second choice and so on...