So I recently learned there's rather grindy tradeskills and a vault, I just hit level 20 and I've been vendoring EVERY drop I get. I did a little reading and I see you can salvage weps, do crafting with gems and such. I've been getting some drops like amythest and different gems, weapons that seem relatively rare and I could potentially salvage them, materials that sound craftable like bolt of gossammer and different cloth and such....

Should I be saving any of this if I am potentially interested in either crafting myself or selling it to other players for more than it vendors? How do I go about sorting loot?

You can sell all "grey" loot.
If you find low level weapons/armor you can potentially salvage them, but it's usually not worth it. For salvaging you have to have a crafter with salvaging skills (woodworking for staffs/bows, metalworking for reinforced/chain armor and weapons, clothworking for leather/cloth).
You'll need roughly about 100 skill for every 5 levels of the item.

You can potentially keep all cloth/metal for crafting later, but again, the low level stuff is not worth it, it just jams your vault.

All crafting materials for leveling your crafter can be bought from vendors and it's your choice which material level you keep.

For making money from salvaging you will want to have drops which salvage for metal bars (reinforced, chain, plate, weapons), because for making trinkets out of these you only need these bars and no additional materials.

The 'gems' you get as drops are not the same as the gems crafters use to imbue weapons and armor. The dropped gems are sell loot.

Thankyou both!