Review what knowledge of math you already have. You probably studied math before and already know the basics, such as arithmetic: addition, division, multiplication and subtraction. Think about what kind of math problems you can solve. You can also take math tests by following a link in the Resources section. A formal test will help you objectively evaluate your current knowledge of mathematics.
Determine what exactly in mathematics you need to learn. Mathematics includes many branches, such as geometry, algebra, calculus, probability theory and applied mathematics. You may wish to learn all of them or only certain branches. In addition, the depth of your knowledge may also vary. For example, you can learn high school math or the math as it is learned by mathematicians studying for a master's degree.
Identify the materials you'll use to get from where you are today to where you want to be in terms of your knowledge of mathematics. Books are essential at this point. There are thousands of books intended for different audiences, from mathematics Ph.D candidates to 3-year-old toddlers. Choose the one that suits you most.
Hire a tutor. While books are good, a tutor is better. The tutor can also speed things up -- remember that you want to learn math fast. The best way to find a tutor is to post an ad online or in your local newspaper.
Work hard. The more time, energy and effort you put in, the faster your learning becomes. Ideally, study as it were your day job. If you are employed full time, use all the spare time you have on math. Also, cut the amount of time you spend on entertainment and other non-essential activities.