First, if you have not yet chosen the facility, approach the process methodically and consider getting professional input (what is right for her needs, as well as which local facilities have high quality care). Ensure she is engaged in the process and decision making–and take time to listen to her concerns, not rush the process, etc. (where feasible). Remember, giving up belongings and a long-time home has many emotions and takes some processing.
Meet and engage the staff at the new facility, to get their help in navigating things like activities, dining etc. (the whole seating thing and social groups can feel a bit high schoolish sometimes at some facilities). Help Mom to let her friends and family know–maybe create a nice moving notice and help her send them out or even have a little "housewarming" party. Visit and stay involved, make sure she doesn’t feel like family/friends are ‘abandoning her". Most places have a lot of great activities though some people jump in to those more or less, whether it just takes a while or some people are in to certain activities only or not big "joiners". You can help her find out which things she might enjoy and/or ways to modify/stay involved with her current interests even if some take place outside the facility.
We offer more tips on moving day here, which you or others might find helpful if the move has not yet taken place: http://info.agingwisely.com/blog/bid/49935/Moving-Day-Making-the-Best-Transition-to-Senior-Living