Step1
Find a radioactive spider, put it on an arm or other extremity, apply enough pressure to make it really mad so that it bites. Super powers: spider sense, increased agility and speed, super strength, ability to adhere to walls, quirky sense of humor.
Step2
Fly into the planet's atmosphere. Find an area saturated by gamma radiation. Fly your ship directly into the rays. DNA alteration will ensue. Superpowers: include super-stretching ability, ability to create force fields and become invisible, ability to "flame on" and fly. Note: there have also been results of a more negative nature, including skin texture and pigment changes, which are not reversible, though super-strength is imparted.
Step3
Sell soul to the devil. Superpowers: flaming head, amazing motorcycle-riding ability. Other superpowers such as magical powers, a living symbiotic costume, and practically omnipotent power can by spawned by signing a contract with Satan.
Step4
Be born on Krypton, or another world with a red sun. Superpowers: super-strength, x-ray vision, heat vision, ability to fly, invulnerability and super-speed. Drawbacks: tendency toward being a martyr in personal life.
Step5
Find a way to mutate genes within current body. Superpowers: there are a host of powers that can result from genetic mutation, including, but not limited to, the ability to control weather, read minds, control minds, use magnetic forces, and heal self, as well as more dangerous powers such as the ability to harm someone with a touch. Tip: wear gloves.
Step6
Seek out immortal god-like being and become its herald. Superpowers: "Power Cosmic," absorb and manipulate the universe's cosmic energy, indestructibility. Avoid those who have superpowers listed in #1.
Step7
Soak in a sewer where toxic waste has been dumped. (This works more efficiently on baby turtles.) Superpowers: amazing ninja stuff. Drawbacks: unfortunate surfer epithets may burst forth at any given moment.
Step8
Become a fighter pilot, break the speed of sound and, at the same time, get struck by lightning. Superpower: super-speed. Drawbacks: snickered at by others with more amazing powers.
Step9
Get a magic ring from a council of extraterrestrials. Superpowers: ability to accomplish anything within the imagination of the ring bearer and according to the strength of bearer's will power. Tip: don't misplace accompanying lantern which recharges ring.
Step10
Fuse body with a symbiotic alien life form. Superpowers: superhuman strength, increased agility and speed, the ability to adhere to walls. No spider sense. Drawback: probably not cool enough to rate more than 15 minutes of screen time.