There was a good article in the Forward containing some Shul Security Tips. Here is a link to the article. Here are the tips.
1) Strike the balance between preparedness and paranoia.
2) Use technology where it’s prudent.
3) Develop a synagogue security plan.
4) Take advantage of the physical security you already have.
5) Install video surveillance.
6) Design a plan to cooperate with local law enforcement.
7) Train synagogue leaders about security.
8) Engage the community while leaving most of the responsibility on the staff.
9) Apply for a security site visit.
10) Consider active shooter training programs.
11) Assign patrolling staff.