Your question is very genuine. Today, It is trend to increase Facebook Page Likes in Online Marketing Field.
Before few days ago, I read that -
(1) We have to concentrate to promote our Facebook Business Page at Other well-known Sites like Google Plus, Pinterest, Instagram and Twitter also.
(2) Whenever you comment at other posts, please use Your Facebook Page Account instead of Personal Account.
(3) Do Not Forget to keep engaging at other Facebook Pages which have more likes.
(4) Be Regular to share your thoughts with other active Facebook Users.
If I will get something new about this topic then I will get back to you soon.