I recently helped my wife launch her own online jewelry store.

It really depends on budgets but in her case, she didn't have a huge one. Here's what I told her to do:

1) make sure to build an email list from day 1
2) Use instagram to engage with your target clients (don't sell, but inspire)
3) Start promoting your store with friends on Facebook and have them like your page. Then create facebook ads targeting friends of friends who like your page with your picture on the ad since they're familiar with you.
4) Consider adding your products to marketplaces to generate income faster (Etsy, Amazon, ebay)

That's what she started doing and slowly implementing things.