As a self-acknowledged "smarty pants", I really would advise against playing dumb (unless we're talking some 48 Laws stuff). I sucked with ladies, too, but it's because smart men live in their heads - the same mistake a lot of women do! We make the mistake of thinking that what's of value to us (intelligence, smarts) is of value to them, and mistakenly in the same way that it's of value to us, too!
Smart guys display intelligence among each other in very dominant fashion, intellectual one-upmanship. And women might find men peacocking versus other men attractive. But if your intelligence comes across the same way to women, then the dynamic has the risk of being that of a teacher and student. And it can make her feel stupid.
If you're "doing you," and she happens to learn from you, then that's great. But the moment she feels you are displaying your intelligence to her, then it can reek of desperate demonstrativeness and snobbishness, whether you mean to or not.
Gotta make it effortless, which is all about modulating how you interact with women and men. Use this line as a guide...
"Humor laughs with; wit laughs at." Women like men who are witty - only when they're with other men. (Or during the flirty phase if she's a b*tchy type, too!)