There are many different techniques that you can do using drywall mud. You will want to properly prep the wall so that you have proper adhesion, something to consider will be to look into the desired look you are wanting to achieve so you can read up on the application techniques prior to starting. You will want to pick a look that is pleasing because once you make a commitment to doing this there will be a lot of labor involved in removal.
Normally my advice would be to consult a professional but this is the diy forum.
Normally my advice would be to consult a professional but this is the diy forum.