Since you're a guy, cultivate some female friends of the platonic variety - friends you can talk about anything with. Nurture those friendships and learn what a 'real woman' is truly like, not the 'entertaining on best behavior' phony kind of stuff most gold-diggers will put out on dates. (And if you fall in love with one of those friends, treasure it.)
Have your female friends evaluate your girlfriends and really listen to what they say. Women can spot a gold-digger and don't like 'em any more than you do. They give all of us a bad name.
Don't be in a hurry to 'lock this one up' before she gets away. The best relationships take time to develop and you want to watch her behavior over time. It's easy to 'play nice' for a little while, but materialism, selfishness, greed and unkindness have a way of showing through if given the time. Look especially for unkindness to others, not to you. She'll be on her best behavior toward you; but the behavior she shows to others (especially the 'little people') is a more reliable indicator of the 'real' person.
Don't be a beauty *****. In other words, if your main asset is money and professional status and you're looking for a woman whose main asset is beauty and sex appeal, don't cry 'unfair!' if her values prove to be as shallow as yours. Look for someone who can bring more to the table than temporary beauty.
And lastly, do know what you're looking for in a life partner. Do you want a woman with a fulfilling life of her own? One who will not be miserable and lonely home alone while you're at work? If you want an equal partner, then be prepared to accommodate her legitimate career goals also. Or do you want a stay-at-home wife and mother who will make taking care of you her #1 priority? If so, don't begrudge her alimony in the event of a divorce, because sacrificing her own life to support yours costs her a viable economic future.
But seriously - The best way not to get taken by a gold-digger is to look for 'substance' rather than beauty in the women you date. Character ages well.