Hypnosis isn't very difficult, but it may be a little hard to start out with, since it takes a little practice.
Taking a course will give you both the guided teaching and some experience at putting people under.
But if you're into the idea, and want to know more look into books like Monsters and Magical Sticks: There's No Such Thing As Hypnosis? - which I found great help in, since I know have a far more productive view on what hypnosis "is".
I've hypnotized very few people, and mostly in sexual content, not into pure sleep-trances. but if you bring a person across several representational system, starting with their preferred one, and then including more and more vivid descriptions of the other senses, the person will usually get blank and their conscious processes will be focused on the imagery you are feeding them, at which point you can toss in suggestions and/or just tell the person "close your eyes, and go all the way down." It helps to have heard some hypnotic inductions (you can probably find some at Youtube) and to have practiced pacing and leading in body-language (such as breathing, and blinking rate) and be comfortable entering states yourself first.
(mind you, the first times I tried silent induction the woman got extremely turned on, as well as getting the glazed look in her eyes.
Pace breathing, blinking rate and posture, then gradually slow down breathing, deeper breaths, slow down blinking rate, and relax your muscles, your facial muscles I've found to be pretty helpful.
If the subject resists, like smiles or something when she notices she's getting affected, smile a little with her to show it's all right, then relax that smile as well, and when you see her relaxing her facial muscles, breathing is slow and deeper, she may have stopped blinking, or just slowed down the rate, you can say "sleep" while e.g. squeezing her hand or touching her forehead.)
You can always go for the extremely fun Milton approach which involves going so heavily into non-sequitur and distracting the conscious that when you toss in a suggestion her mind claws to it since it's an escape from that chaos of logic.
But seriously,
I haven't had any courses, but I've listened to some inductions, watched some on Youtube (some proper ones, like http://www.youtube.com/watch?v=oRTg2xHc1U0 ) pay attention to the whole thing, notice more details as you watch it over.
Like the authority which is established in the movie ink above ("who's the hypnotist?") and the way he paces body language before leading the person to relax, and then handing the suggestion.
You can also look up stuff like the Handshake Interrupt, or other fascinating inductions.
I also recommend getting books on the subject, make a little hobby out of it, and either learn yourself by having willing subjects or go take a course and get a little leg up from people who work with this for a living. (make sure it's quality though before you sign up)
cheers.