Cool. This guy is a really good teacher and has great videos:
http://www.weldingtipsandtricks.com/Mig-welding-tips.htmlYou want that sound. If you are struggling, get it mocked up and let a professional tidy everything up for you when you get done. If you get good weld penetration, but the look isn't what you want, don't be ashamed of the flap wheel. You just want to make sure it's safe.

Are you using wire feed? MIG with gas? Looks like 120v?
I borrowed a 120v MIG on my build and it was a little tough to dial in. I was able to get strong welds, but I wished for a little more heat, but it just wouldn't weld well at the highest settings. I had to weld a little slower to get the penetration and ended up with a tad more filler than I would have liked. Slowing the wire feed down just burned off the tip of the wire. Just part of the territory when using a cheap welder, but you should be able to get decent results.