You'll find pages and pages of information around this site about canker sores and how to get rid of them - but the video below (from a slightly quirky English dentist) gives a good overview about treating and preventing mouth ulcers in general.
He talks about both canker sore ulcers and herpes ulcers - and also mentions the kind of ulcers that can point towards mouth cancer problems. You certainly don't want to miss out on the latter information.
When trying to figure out how to get rid of canker sores the decision mostly falls between whether you want to use conventional medical treatments like hydrogen peroxide, lysine and steroid paste .... or whether you prefer to go down the home remedy route with salt, lime juice, baking soda and other related tricks. There's no right answer but if you browse the pages on this site you'll certainly find plenty of suggestions.
Dental Care:
How To Get Rid Of Mouth Ulcers