TL;DR: Don't mix and match Equipment set types or levels if you want to obtain set bonus effects.
How to optimize your equipment crafting efforts:
First, when you have 4 or more identical “common” items, you can “Combine” them via the Inventory screen (chest icon, then select the “Materials” tab) into 1 higher quality “uncommon” item. Click on an item you have 4 or more of, and select “Combine”. This will improve your odds of crafting higher Tier items.
Second of all: don't mix and match items between “Sets”. There are set “bonuses” that only apply when every equipped item is from the same set. I've seen multiple people make this mistake, and it significantly reduces the value of their crafting.
This mistake is especially common once folks upgrade their Forge to Level 15, and can craft Level 15 gear. There are two different sets: “Novice Pirate” and “Novice Adm-inistrator”. If you mix and match these, you are not going to get the bonuses that come when you are wearing items of the same set that are all Tier 3 or Tier 5 (additional bonuses). You can see a list of the bonuses when you select “Set Details” at the top of the Set Screen.
Choose one set type or the other, and focus your crafting on getting every item in that set up to at least Tier 3, and better yet, Tier 5.
You can see what items you have equipped on the Captain view screen. Click on the item to see its properties, and see what other items of that type you have available to equip. Mixing and matching is o.k. if you do not have a complete Tier 3+ set, but you should make a focused effort to obtain one ASAP.
One other note: you may be unable to craft a particular item because you lack the Materials. These can be obtained via the “Market” in chests, or by hunting monsters. If you click on the icon representing the required material for an Equipment item where the “Craft” but-ton is greyed out, it will list what types of monsters (by level) provide that type of crafting material. You can use this information to focus your hunting on monsters at the appropriate level (10,16, 22 for example).