I'd suggest always trying to use multi-word phrases for tags over single words (when possible, obviously sometimes a single word is long or enough). In this item you use 'blue' and 'teal':
https://www.etsy.com/listing/184325643/turquoise-aqua-beaded-double-strand?ref=related-3Tags are how Etsy search combs through items to pull up relevant searches. If you only have blue and teal (on their own) your item might pull when someone searches for 'blue table' 'blue dress' 'teal mug' etc. And you'll be less relevant for searches of 'blue necklace' than someone who has the actual tag 'blue necklace'. When you use color or material descriptors in tags (blue, hemp, silver, etc) I would try to put in what the item is too, that way you're most relevant for the searches you want to be relevant for.
Also, alllllways use all 13 tags that Etsy gives you. These are your 'nets' for 'fishing' in the pool of etsy buyers. You always want to be casting as many keyword hooks out there as possible that way you'll appear in more searches. Here is one item (that I LOVE) that doesn't look to be using all tags:
https://www.etsy.com/listing/239297984/life-bicycle-poster-85-x-11-original-art?ref=shop_home_feat_4
