I've been looking for advice on this myself and came across this link which was helpful:
Am about to apply it to something I'm working on. There's a useful bit from Mr Tom in this link (#8 reply) that explains it a little better.
This advice is only good if you are using frame animation. It does not apply to timeline animation which would require you to adjust the fps found in the menu located in upper right corner of the timeline panel. Just click the icon.
Keep in mind the fps is dependent on the web browser. Therefore anyone wanting to set the fps to a faster rate may find it does not work.
In this case rending out a video would be a work around.
A video is a format like .mov, .avi, etc.