I believe a persons resourcefulness is derived from their adaptability. A resourceful person is an adaptable person. Instead of just simply being able to use the resources available to them, they are able to use their creativity to overcome and adapt to the resources they don't have.
Bringing the subject back to myself, above all else what makes me resourceful is preparation. Being as prepared as I can be for any situation I am entering into is what makes me so adaptable. Whether it's something simple like plotting out a route on google street view for a location I have never been to before or something more complicated like researching a super villain I have to deal with as a super hero, preparation is key.
Being prepared allows me to be able to anticipate possible problems often before they even become problems. In the same vein as preparation and research, the ability to continuously learn is what I believe to be one of a persons most valuable characteristics for not just being resourceful but for life in general.