I would try to avoid shaving/clipping a ragdoll if possible. They have such a lovely coat and it often doesn't grow back quite the same after a clip (sometimes coarser hair, and often much darker). I'm a former vet nurse and have groomed a few ragdolls in my time. Cats generally need sedating if they are going to be clipped, or if they are going to be intensely groomed due to matting. If your ragdoll isn't matted though I'd just get a good wide-toothed comb and a slicker brush. If you can afford it you could also try a Furminator. They are great at removing loose hair.

Also, a good thing to remember is that their coat is actually helpful at keeping them cool as well as warm. And if you have the cat clipped you may have to think about sunscreen if the cat goes outside because a lot more sunlight will penetrate through the fur that's remaining.

PS. I looooove ragdolls. They are so beautiful to look at and generally have such a lovely temperament I talked about getting a ragdoll one day so much that my best friend ended up getting one! Haha