Congratulations, becoming a Mad Scientist is a worthy career path that offers many rewards. However it does take a lot of hard work. While many mad scientists (ie: Bill Gates) got lucky and shot to the top of the Mad Scientist ladder, the typical path is much harder.
First you have to go to a Sinister School (grades 9-12) this is pretty easy, most American High Schools are designed to give anyone with a IQ of over 4 a resentment of the world.
Next need to attend an Ominous University. Universities do not turn people crazy; they just give the crazies a chance to shine. This is the place to hone your philosophy on life, preferably with its own warped and highly detailed moral code. Don’t worry if you have put no thought into the reasons why you have made a rule, the important thing is you believe your rules are superior to societies in general. (ie: Killing is wrong, unless done on alternate Tuesdays, while wearing a bandana).
After graduation you’ll probably have to get a job as Bad Tempered Tech. This is where you will practice the monotonous tasks that are important for the advancement of science, mad or otherwise. You will want to work hard to get passed this phase as quick as possible.
Hopefully, after being a Bad Tempered Tech, you can get a grant or work for a company that will bankroll the investigation of one of your scientific principals that you will need later when you are a fully accredited Mad Scientist. At this point you will be an Irate Researcher. This is actually a very important time even if it is not terribly glamorous. For instance, if your goal is to be Mad Scientist who takes over the world with a Death Ray that fires Omicron Radiation, it helps great deal if you are first an Irate Researcher who investigated Omicron Radiation.
After this you can move on and become a Deranged Theorist, This is where you can work on the mathematical principals behind the horrendous inventions that you will unleash on an unsuspecting world.
Unfortunately the pay for being a Deranged Theorist is fairly bad until one of your Theories is proven, so you will probably need a job to support yourself in the meanwhile. Most Deranged Theorists work as Evil Professors during this period in their life. While it is possible to become both an Evil Professor and Mad Scientist at the same time, it is almost necessary to wait on your plans to rule the world until after you get tenure.
Once you get tenure as a Deranged Theorist/ Evil Professor you are in a perfect position to gather up all the things you will need to become a Mad Scientist bent on conquering the world. You can make money on the side as a consultant, you can gain access to a large lab with plenty of grad students/ Henchmen. You will probably even be considered an authority in your field.
That is where you run into the final hurdle, as an authority it is hard to unleash your vengeance on the authorities as you are one of them and are on first name basis with many others. If you make it past that final hurdle you can join the ranks of the Mad Scientists.