Hey guys, it would be great if you could check out my cover and give me feedback. I've been really working at singing for the past couple of months and I feel like I'm getting a lot better.
If you could make one suggestion to improve my singing, what would it be?

Thanks in advance!
Quote by UseYourThumb
Well thanks, but telling someone to simply improve their pitch isn't exactly a critique at all...

Actually it is a real Critique.
He's telling you (politely) that your singing was out of tune from the guitar.

Out of tune singing
Poor Dynamics
Rushed Phrasing of lyrics.

Here's vocal exercises I do with the instrumental versions I learn.

Sing the notes you are playing on the fretboard instead of the lyrics.

Record and play back your singing, you'll be able to hear the out of tune sections and know where you need to practice.

Listen & play/sing along to the song so much you get sick of hearing it
or better yet
Get the backing track either free or otherwise.
A good source for free backings tracks is:

Thanks djmarcelca, that's more of what I was expecting. I need cold criticism- not something that won't hurt my feelings. That exercise seems like a logical way to approach things. Thanks!