Hi Sepul,
Firstly don't get too tied up too quickly on trying to perfect your brewing process.
Most of us started off where you are, and I think its good to try and not make it too complicated too early on.
As others have mentioned the simple act of replacing sugar additions with malt extract for the can kit will result in a much better beer.
Also malt (DME) is mostly fermentable, but also contains some many important elements required for healthy yeast production (such as FAN etc) that is missing in the more simple sugars. The malt also leaves some body behind which usually results in a more fuller and richer tasting beer ( as opposed to the watery thin taste you get with straight sugar ).
Unfortunately you don't really have any idea what has been put in the can kit (and they are doing it to make a profit, ie cheaper ingredients), and what sort of quality it is, so you need to assume its not going to be top notch. Hence the malt addition is a good start as at least you know it will improve the standard of the overall beer.
The next step is to start adding some hop additions, and from there dropping the can kits all together and making your own recipes. Some people never get this far and are still more than satisfied with the beer they produce.
Of course if you get hooked, you will eventually have to cross over to the dark side of all grain brewing
![Wink ;) ;)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
... but that is another story.
So start with the malt extract, then move onto some extra hops, then when you start understanding (and have experienced) a bit more what is going on start moving to do your own thing and ditch the can kits.
Also a great way to explore craft brewing further is to get involved in homebrew club and of course keep posting on AHB.