They should come to in a couple of seconds on their own. But I always was taught to err on the side of caution and help them out. Lifting the legs is a good one as it forces the blood towards the brain, opening up the arteries that might be compressed. And doesn't involve moving them around too much since sometimes folks will come to still trying to struggle if it was during competition.
I've seen the one used in Judo to sit them up and put your knee in their back to similate a breathing and moving motion, but I like the legs up method most. Yeah and the dreams are wild
My personal fave time was when rolling with my old instructor who caught me in a cross choke from the mount. I saw it coming and thought if I bridged at the right time, I could keep him from sinking it. Apparently, not
I heard myself snoring as I woke up in his guard with him smiling. I said, "I think you got me." and he laughed and said, "I think so too."