1. White Elmer's Glue. I haven't tried it on other white glues. I tried using the Washable No Run Gel, I'm still waiting for what it would come out.
2. Tissue Paper. Just your plain old tissues. Nothing special needed.
3. Foam/Brush. Or you could use your hands.
4. Foundation/Concealer. To give the prosthetic skin-like color.
5. Blower. This is somewhat, optional, it makes the job faster.
6. A base(Tray, Baking Pan, Any smooth surfaced platform. I used a book and plastic folder). This is very important, your whole project depends on this.

Once you reached four(4), or until you think it's enough, you apply another layer of glue over it, but do not dry it, put a layer of tissue paper over it and damp another enough glue to cover the tissue layer. I suggest that you do not pile layers of tissue paper since it would be hard for the glue to dry, and it would make the prosthetic not pliable.

After it dries, really really dry, it's time to peel it off. Every after you peel, you, again, apply/brush another layer of foundation below, to remove the stickiness of the peeled surface and to add the same skin-like effect. Keep doing this until you peeled the entire thing off.

This one's without the foundation/concealer. This was my first try. The surface is rough and the back is smooth.

EDIT: It came out nicely(not perfect though). I'll be posting a tutorial soon.  

EDIT: I'm going to try out the one made with gelatin mix and glycerine(though I   need to buy glycerine first) then I'll make the tutorial and review about it. *MEEEP*

DISCLAIMER: PHOTO NOT MINE

1. Go over multiple tutorials and try them yourself until you think you got it.
2. Earn. Earn sufficient money so that you can complete every single bit of detail of your character. Cosplay is about art and craftsmanship, also being critical, observing the smallest of details.
3. Inquire/Ask cosplayers who have been in this league for a long time. Ask them about the wigs, the shoes(because some characters require custom boots/shoes), the weapon/props, the accessories, the make-up and the look.
4. Think of alternatives. Your characters are fictional. Most of the time, the item that would complete the look can't be found on any store. Make one.
5. Think a bunch of times every now and then.
6. Be careful of scammers Be sure to buy only to legit online sellers if you are to order your items online and be sure to differentiate what's good and what's not if you are to buy offline.
7. Have fun. Spectators like me like seeing barkadas/tropas cosplaying epic characters and having fun.

Cosplay (for me) is a hobby where you can express yourself. You can "unleash" your inner artist in you by sewing your own clothes and making your own props for example. It's not where you just pose for the camera and smile. It also means portraying. For example: "A Ciel Phantomhive cosplayer was asked by a photographer to pose for him, then the cosplayer poses and do the usual cutesy-pose. Then here I go, approaching to the cosplayer to talk to him because I'm not allowed to punch him directly to the face." This is the reason why when a person asks a cosplayer on "how to cosplay" they usually answer, "it's best to portray you favorite character," Why? Because you know them by heart. they would never recommend by saying, "JUST LOOK FOR NARUTO IN GOOGLE. .YOU'LL SEE EVERYTHING IN THERE," That's just b*s*. Basically, when a person cosplay, the people should see the character that the person is portraying, NOT the person in the character's clothes. That's why most people are confused about costuming or costume-wearing with cosplaying. I repeat, cosplay is a hobby, not a stepping-stone for popularity. Never expect that when you do this hobby, you'll be featured in TV or in any kind of media, this was actually just for fun in the first place. If you want to cosplay with that in your head, I'm telling you, you better change your opinion about it.