It sounds like you've not gotten too far in and/or not had a variety of drops, so it looks weird, but most of the armor you can make has upgrade slots. There are also around ten billion upgrade-part schematics. They're all useful depending on what you're doing.
Please note that the word "better" as you're asking, and as people are answering, is extremely situational and subjective. The naming conventions are not really consistent, and as far as which schems have upgrade slots or don't, the only way to know is to know. The wiki page listed by shazza above is a page I have open all the time.
For example, you may have an armor schem and a leg upgrade for it with a bunch of Defense: X Cloth slots. Later you get a "better" schematic that has only metal and leather Defense slots. Well, if you're a little underleveled, or on Nightmare, and you decide to go take on a Lightning-based dragon, the "better" schematic is not as useful, because cloth Defense slots provide electric resistance.
Once you get a feel for which materials do what in the different slots, you'll be able to make stuff for anything you feel like doing. If you don't want to micro that hard, you can just go for more general-purpose stats and call it a day.
Side note: if you get a new schem and don't feel like tabbing out to look it up, I find it useful to make one with Tier-1 mats I don't need any more, and then you know for certain if it does or not. You can also that way see what it looks like, and with different color schemes.