Just keep practicing and you'll get the hang of it
I would get a piece of .100 or .125 scrap and weld 2" passes to practice. This will help you set up your machine and help you with your angles, speed, etc. As far as setting up your machine for wire speed and etc everyone welds differently so the settings could/would be different for everyone.
As far as pretty welds, with flux core it would help if the welds were smooth and consistant so that you won't trap the slag in undercut or overlap.
Nate