Everyone is capable of performing magic regardless of whether individuals in their family have or haven't done so (which is what I'm going to assume you are referring to by "having magic in your blood"). You simply need to know your basics. These include:
*Belief in yourself and your abilities
*Circle Casting and Releasing
*Correspondences (colors, days, lunar phases, etc)
Please keep in mind that depending on who you talk to the basics can and often do differ. You can add to this list or take subjects from it depending on your interests or what you feel you need or don't need to learn. However, I suggest studying all of them because you may very well need to know them in the future.
Information on the basics can be found in Newbie Central, Tips, and Faqs. All of which are located on the Home Tab.