If you aren't truly a geek at heart, it's risky trying to become one. You might end up becoming a dolt. True Adorable Geekdom is only attainable by naturals.
Stay away from Suspenders, if you don't know what you're doing. It can turn you from geek chic to "geeky fashion victim".
This style is recommended only if you are college-age or younger, preferably, or in a profession receptive to such eccentricities. Geek chic fashion has become widespread to girls ranging all the way back to pre-teen age. Considering that more mature male geeks tend to dress and act more conservatively, geek chic is closely associated with "young" and you run the risk of either attracting the wrong types of men or not being taken seriously by the right types. Remember, true geekiness is not a fashion, it's a state of mind.