See let me tell u in short.
Firstly , to take part in counselling u must checkout the last year; cutoff of last rank intakes of respective college u prefer or u desire.
Then compare u ranks to it.

Now take part in counselling.
For which u have to register urself online.
They will ask u to fill choices of colleges u want.
Now keep in mind the cutoff rank u compared will now help u.
So according to ur rank fill ur choice like if u got 2000 rank so basically fill ur choice for the last cutoff of good colleges. Ur preferences of choice of college will help u to allot u a good college.
And one more keep on participating till last counselling as it will upgrade ur college.