Although your own internal measurements are the most important, you will occasionally need to seek external feedback on your progress toward your goals. When you do, be sure it is from people who are truly interested in seeing you succeed. Don't seek feedback from fair-weather friends, competitive peers, or any person who doesn't have your best interests at heart. Neutral doesn't count. Get feedback from someone who is on your side but will still be objective and honest with you.
I've observed time and again that misery truly does love company. Jealousy creates some of the most miserable people I know. Surpass the achievements of your particular social crowd or your business colleagues, and look out for the slings and arrows of those who wish you were back where they are. You have to dodge the snide remarks and catty comments. As they say, be like the duck. Let them roll right off you. Don't internalize them.
Only pay attention to feedback from those who have similar goals or who are working actively alongside you to achieve goals of their own. Motives and fears run deep. The sympathetic fair-weather friends who support you and comfort you when you're down, may like you best when you are in just that state: down and dependent.
Ultimately, nobody else is responsible for your life but you. Nobody else is accountable for your actions but you. Therefore, nobody's expectations for you and opinions about you are as important as your own. So make sure those take precedence in your mind over all others, and if you do need to consult with someone else, think very carefully before you choose exactly who.