Hey Harshita !
Going through the cutoff of Assam Medical Colleges in 2018 through State Quota, students there generally placed the colleges according to this preference order :

1. Guwahati Medical College, Guwahati
2. Silchar Medical College and Hospital
3. Assam Medical College, Dibrugrah
4. Jorhat Medical College
5. Tezpur Medical College
6. Fakhruddin Ali Ahmed Medical College, Barpeta.

You can follow the same order or even put the college nearest to your home as Preference 01. It won't matter much because academics is more or less quite same in all.

Good Luck !