Ohkay...First up i found the vic, but you got the wrong link up, fix that... (after you do that)you gotta learn the advanced techniques before people can really help you out... Look through the melee discussion forums and read the advanced techniques thread... after you get the hang of l-cancelling, shffling, and wavelanding (or watch wak's advanced how to play videos)... then start watching pro vids, and watch how they play... About dr. mario, he should be played as a combo machine (more of a juggler than combo'er) and eventually you should able to do that... And for some dr. mario specific techniques watch "the doctors checkup" by smashmac...
I also noticed an up+b as an attack... its pretty much worthless, there is almost always a better option (unless you cancel it, but its really hard to get the hang of and still kinda worthless)... When you recover coming back to the stage, try not to land on the stage with the up+b, try to just catch the ledge so you cant get hit so easily...
stop rolling so much...