The majority of your shop traffic comes from searches, either within Etsy or through another search engine, like Google. Therefore, it is vital you properly and optimally tag your listings. Here are some tips to help you:
Use all 13 tags! The more tags you have, the more likely someone will find your items.
Use two- or three-word tags. One-word tags are too broad; any more than four are too specific and probably won't fit in the 20-character limit. Describe the:
item: crocheted baby hat, beach photography
color(s): pink (generic), magenta (specific), black and white
shape: geometric, round, abstract
material: wooden, felted wool
size: 2x4 inches, 5 mm (always include metric to bring in international buyers), XL, 3-6 months
era (for vintage): Sixties, Victorian
brand (for vintage and commercial supplies): Disney, Studio G
use: embellishment, home decor
recipient: toddler girl, men's, dog
Try different word combinations and synonyms. For example, here are the tags for my most-viewed item: vintage owl, vintage figurines, owl figurines, vintage owl figurine, brown owl, ceramic owl, vintage 70s, vintage seventies.
Check your spelling. However, if your item is commonly misspelled, then including the misspelling in your tags may be a good idea.
Review your shop stats. See what words are bringing people to your shop. Change tags that are not bringing in views.
Use Etsy's search box for ideas. Start typing and see what word combinations show up to get an idea of popular searches.
Follow Etsy's rules of tagging. Read them here for more tips and dos and dont's.