My best advice is to do giveaways... we do gift certificates for the salon, lotion, and we do other non-related items such as waterpark passes on our waterpark passes we had almost 5,000 views and mind you we are just a small salon with 12 units in a town of 18K with lots of other salons in our town. People love free stuff!!!
There is a ton of creative fb ways to build likes if you google them, but giving away free stuff definitely helps.
Pictures I think are important when you are posting, if it is plain text its not as eye catching and it often gets skipped over. You can share info on products, pricing, specials, staff info, hours, equipment, tanning tips or just because post.
I encourage to use the post scheduler to schedule future post out and do a bunch at a time. I do mine each week typically for 7 days at a time so I don't have to worry about a new post each day. Also post aleast 3 times a week so your page stays revelant and fresh.
Lastly, I always say go the added value route vs discounting ...like instead of giving 10% off give 5 days free or something and you can make it necessary to receive discount you must show us this post or that you have liked our page etc.
The sky is the limit with facebook and you reap what you sow with it. Best of luck here is mine if you want to check it out for ideas
www.facebook.com/esglow