The first thing you need to do is to determine whether you really have any musical talent. This could involve singing or playing a musical instrument or both. You may need to ask others for some objective opinions about your abilities and potential. Whether you accept their assessments is totally up to you.
Take music lessons. Find a good music teacher and learn how to play an instrument, such as the guitar, bass, drums or keyboards, that are commonly played in rock bands. If you sing, consider taking some voice lessons to show you how to use your voice optimally. Learning to read music and developing an ear for what sounds good and what doesn't is needed to be a good musician.
Listen to other rock bands you admire and learn what makes them stand out.
When you have developed as a musician, look for other musicians who share your passion and work on forming a band with them. It's best to audition them first, however, to make sure that their abilities and style are a good fit.
Get good equipment. The better it is, the better you will sound.
Rehearse. It takes hours and hours of dedicated rehearsal time to develop your sound and to learn to work together as a group. All of you should be able to give and accept constructive criticism in order to improve and grow as a band.
Write your own songs. Lots of rock bands may start off covering songs by other artists, but, if you want to draw more attention, coming up with your own original music is the best thing.
Start performing anywhere there is an opportunity to do so. The more exposure you receive, the more the word will get out about your rock band.
Find an agent. If you believe your band has what it takes to make it big, find an agent, who will aid you in getting more gigs, preparing a demo and getting your name out to record labels and the like. Don't expect this to be easy, however. There are many rock bands seeking representation from agents, so there is a great deal of competition. Make sure any agent you may be considering is a reputable person.
Persevere. The music industry can be very tough, but if you really think your band can be successful, keep pursuing your dream.