Thank you so much you guys! You are so helpful! I should try your techniques. Once again, Thank you!

Personally, if you want a smooth clean render, you'd want to fill it in with the color of the character's fur. But of course, there are many ways to do that. If you want to use borders for the markings, then do it slightly darker. Not black.
In the image you presented, there are noticeable white specs, which you'll want to cover up. If you're using paint, (which I'm guessing you're using) I made a graph to help you.
http://oi41.tinypic.com/2l91paq.jpg
From artist to artist, there's some ways to improve.
Second, you will need to crop the large space on the image. It will undoubtedly get deactivated if there's that space there.
I'm not sure if it qualifies as a bad render or not, but those are what I would change. Hope I helped!

Ah, ok C: You mentioned the lineart and I got slightly confused xD

Celeste> yes i know what he's talking about, when it comes to renders, i prefer personally seeing the markings in liness, i considere it lineart too, same as in my drawings, i considere lineart facial touches, wrinkles and hair,

Nikon- Baltolover is talking about the marking lines, not the actual lineart colour c:

I'm not very supporter of renders, but I personally don't agree with Celeste, I don't think the lineart looks better in the color of the character's fur, i peronally prefer darker colours, but that's a matter of each one's taste

Now about it being bad, i recommend to take a look at the rules, there is a small guide steet posted in the forums about what is considered bad and what is considered good

http://www.animationsource.org [...] -rules-bad-renders-t35764.html

It's not considered bad, but renders and coloured linearts always look better if the lines are drawn in the colour of the character's fur, lining the fur in black doesn't look as good.
So no, I don't think it's considered as a bad render, because it's a coloured lineart.

your picture looks great theres nothing wrong with it its much better than i can do