Improve google visivlility

I have a dentist site for over 3 years now. I need to improve my Google ranking and be in the top 2-3 position for my few keywords. Clean methods only! Bidders should have high ranking here and be able to provide references from similar jobs. Will pay final balances only when goals are achieved. I am ok to agree on monthly payments. I understand that the results cannot not be reached in a week...