I am surprised that no one has recommended preheating the metal prior to starting. With those low power wire feeders, it is should be taken as a requirement on anything thicker than 1/8". It will allow you to run fewer amps (slower wire speed) and still make it penetrate and make a more uniform appearance. It unfortunately wont make up for any erratic movement of the gun. Even if all you have is a propane torch, preheating the metal to at least 250F is going to help it fuse better and also remove any moisture in the metal that would cause porosity or hydrogen embrittlement or cracking. Try that next time you feel the need to weld something more than sheet metal. Even sheet metal wouldnt hurt to dry off the moisture first.
I have one of the little 110V Mig/FCAW welders that was given to me, but I rarely use it. I prefer stick rod for my work as I dont make a lot of light sheet metal stuff anyway. My welding arsenal is a 350 Amp Miller AC/DC CC/CV machine and my oxyacetylene torch. Maybe someday I will add a suitcase wire feeder to it but so far I just have never seen the need for one. My electrode selection consists of only 3/32- E 7018, 1/8" E 7018 and 1/8- E6010, plus my little wire feeder. If I cant weld it with that, it dont get welded. I also have a soldering gun for the small wiring issues that come up. So far I havent had any thing needing repair that I couldnt fix with this. IF I had any aluminum to fix, I would just take it somewhere as it isnt worth the expense to stock any thing for that for what little if any use I would ever have.