A typical doctor can ensure a comfortable retirement after a 25-30 year career by saving 20% of her gross income for retirement. Saving for other goals (house down payment, new car, college, paying off student loans etc) is all in addition to that. If you are not saving that much, try to increase how much you save by 1% each year and as you accomplish your other financial goals, redirect that income toward retirement savings.

Further Reading:

Safe Savings Rate
6 Reasons to Have a High Early Savings Rate
7 Ways to Increase Your Savings Rate