We can use the arts to spread messages about disability. For example there are comedians with disabilities that help bring humour to the subject of disability. This can help people think about disability differently. If starting out you can appear at open mics which means that your message can get across to people of all sorts.
Bands, if successful can generate a good amount of publicity. It is a good of effort and work but if this interests you and you like traveling the best time to start is now; enquire about a vocal coach. You can even be a solo artist. If you can't sing try being a DJ.
Films and theatre are a good way to tell these are expensive and you may need to seek funding. A good and/or humourous short film should be able to attract a good view count on the internet and is generally a more effective way of spreading messages.
Of course for the more traditional minded people paintings still exist but you limited to exhibitions. If you love to paint; do it! If your goal is spreading your message you may want to choose a wider reaching art form.