Skin Editing Program
First off: using a skin program is recommended for creating your skins! A good program that I personally use is MCSkin 3D, which you can find here! It allows you to see and edit the skin in 3D form, 2D, or split and see both! Download links are at near the bottom of the linked post.
Program Link: http://www.minecraftforum.net/forums/ma ... -mcskin-3d
Default Skins
The default skins are made by Peach & Griff [correct me if I'm wrong] for use of the players! They're nice for a base, though I do suggest you try to make a custom skin or have one made specific to your character!
Custom Hair
Skin Link: http://imgur.com/IQJztO2
Custom hair can by added by putting it to the right of the arm area. If you want to make your character's hair shorter remove pixels from the bottom, but not the top!
The blue is the appropriate place for the hair, and the red is the non-recommended area for hair.
Examples:
Skin Link: http://imgur.com/isUGFR3
The skirt can by added by putting making it 2 pixels to the right of the arms and 2 pixels down from the hat area. This skirt should be 2 pixels wide and can be up to 9 pixels tall. If you want to make your character's skirt shorter I suggest remove one to two pixels from the top at most, and remove pixels from the bottom as needed.
Examples:
Skin Link: http://imgur.com/uB119lq
The beard is similar to the hair layer. I suggest you add the top part of your beard top the bottom part of your head where I put the blue, otherwise the skin on the bottom of your head will come through and it'll be awkward looking.
Examples:
In MPM you can scale your models to a certain percentage to match your character's height which is pretty neat in showing your character's height differences! After you figured out your height you will set all the scales to that percentage. If you want to make them more chubby or skinny character, play with the width and the depth percentages!
floop2011 already calculated and made a doc with all heights from 3'0" up to 8'11", though MPM only goes to 8'5". You can find it here!
If you want to do it yourself, here's how to find the percentage yourself! This is pretty much just copy and pasted from Queso's previous guide.
• For the back hair it is shown MIRRORED compared to the 2D so be careful when doing shading! You can try to compare the examples on the hair examples and their skins to see what I mean!
• You can quickly switch between skins if you have a direct link and put it in the skin url box to the bottom left! I suggest you use imgur, and make sure you use the direct link which has the .png at the end otherwise it will turn you into the default male.
Current MPM Bugs / Solutions
MPM at the moment is being weird and I think it'd be good to point out the bugs.
• It might not show your skin as changed when switched with the Skin Url box. Despite this it should show as changed on other screens! If you want it to switch on your screen you will have to fully restart your client.
• It might also show you with the default male legs. This should only show on YOUR screen, so no worries! Again, like the above, you'd have to fully restart your client to fix this.
• If everyone looks like the default male I suggest you try to reload your skins, there should be a button on the right to do so! This should hopefully fix it! An especially slow internet might cause this too, and that's I can't help with.
• It might remove all your saved skins settings! This is annoying, but I think found a good solution to this though which I'll put under the spoiler below.