1. Total number of fans
Yes, it is an important metrics to follow, although, not the only one. Having a good base of fans is always good for your brand.
2. Stable positive growth
Besides number of total fans, you should also take into consideration the daily/weekly/monthly growth of fans on your Page. Is it relatively stable or are there big ups and downs? Your fan base should be always steadily growing. Make sure you do not start losing fans. If that happens, try to identify why are your fans leaving you. Is it a wrong content on your Wall or simple loss of interest?
3. Regular postings on your Wall
Connecting with your fans on a regular basis allows you to give your fans daily information from your company. Make sure you post regularly and don’t spam your fans.
4.User wall posts and interactions
While analyzing your Page, you should always look into the number of user wall posts and also their interactions (likes and comments on your wall). This way, you are able find out if your Page is “alive”, if it has engaging fans, etc. Having tens of thousands of fans is nice, but they are worthless if they don’t interact with you.
5. Evolution of your Engagement Rate
Keep your audience interested by posting regular and engaging posts. If the total engagement on your Page drops, analyze your content to find out why.
6. Response rate
Facebook is all about communication. Fans expect you to talk with them. Make use of this platform and engage into conversations with your fans. They will appreaciate it.