First of all, I'm really no sig-maker, so I cannot give any gradings or anything for this. But from a purely artistic perspective, I have a few comments.
First of all I feel the "pop out" elements of the image could probably be a bit sharper. Your graphic feels a bit fuzzy. Maybe this is the effect of scaling it using Cubic interpolation? Manually adding thicker outlines to him might also help focusing him more.
The text feels somewhat out of place, introducing a new shade of red to an image that is already quite disperse in various colours.
The pop-out effect looks nice though, breaks up the monotony of the signature rectangle.
.
Griatch

Another name for that process is OOBING (out of bordering), dopey name but the term is worth remembering. I agree the pop out is a little fuzzy but it looks like it was rendered well. I made one a while back and 4 people told me they didn't like it, which bummed me out since I had put a lot of work into it. If you got your pop out sharpened a little I think your sig would be really nice. Don't get discouraged by the opinions you get, Most of the folks here are really nice and anything that seems negative is meant to be helpful.

Yes of course, there would be no point of giving critique if one didn't do it to help the artist. Critique is the absolutely best way to improve, the toughest critiques I've had over the years were also those that helped me the most.
.
Griatch

If you look in-between his legs, there is a white spot there, I cannot tell if that is part of the background, or whether it is part of the render that got missed... I do the same thing a lot don't worry about it.

It's actually a very good start. With each refinement we learn more. Later today when I'm feeling more up to it, I'm planning to do a sig file myself. I do a lot of stuff, but very little in the way of sigs. I have lots to learn and I will be asking for critiques, too. Keep up the good work!

I am for one very happy you finally figured out the process.Looking good!
Keep practicing.

wut do u mean?

it seems like amanda added a different picture in the background and made it blur thats another way of doing sigs as well i kinda know how to do that tho but wut i did was jst practice i wanna do a sig with a border of skulls

thank u man i wanna know how to add videos on sigs that seems a bit harder

The term "critique" means that someone with the skills you are trying to achieve, have given you some advice on how to make it better. So don't take it in a bad way it's only advice.

thx man i jst need more brushes

I was just talking about the render... the sig looks great man

There is white in-between his legs that got missed during the rendering process

Just google gimp brushes and you'll have tons of places to get them.Gimp can also use PhotoShops ABR extension so if you find a photoshop brush you like place it in your brushes folder and refresh your brushes and it will be in there.

Really GIMP handles PS brushes o.O
That is nice to know, one more thing we got on Shoppers

Gimp also handles PS pat extension Willy.
In fact just about any image extension will work as a pattern file in gimp.
GIF, JPG,TIFF, PNG

You can also use SVG gradients in gimp tutorial here
viewtopic.php?f=10&t=1256#p14260

o.O so I can run Photoshop layer files in GIMP? Without problems? and they can't run xcf in Photoshop? Tee-Hee another reason to dislike PS...
Can GIMP save as .PAT?

Edit/Copy - Paste as new Pattern

Also if you copy any open image or selection in Gimp it auto becomes the first brush in your brush dialog (saved in the clipboard)

Only that getting constructive critique is a good thing.
.
Griatch

Deviantart is a really good place to fine a LOT of resources, brushes patterns etc.