This is coming from my personal experience.
There are basically two ways to getting more likes on your FB page, i.e. through ads or organically. Running ads to get likes is the most quickest and effective way, since you will be targeting exactly those who are interested in your content. However, you will obviously have to spend some dollars to do that.
Getting likes organically is little difficult as it requires constant activity on your page and patience. Though it usually depends on how much activity you are doing and how much time you are spending on it.
My advice to you is to actively post relevant content on your page (if itās original, the better), engage with fans on other pages relevant to your page, encourage your friends and family to actively share your pageās posts, and make sure you reply to any comment on your page.
Read the articles others have listed here. It wonāt give you any direct instructions on how to get more likes, but you will get some idea about strategies you can develop to achieve your goal.