It is recommended that you find out from the university you are applying to how strongly they consider the AWA section. The scores for this section are not part of the total GRE score. They are graded on a separate scale out of 6. Generally speaking, a score above 4 is enough to get you into a decent college but if you are seeking admission into an esteemed university like Harvard, you need to aim for a perfect score of 6, or at least a 5.5. A key thing to note is that your AWA score can also be used to judge how authentic your SOP and application essays are!