Same as a non-mirrored database. What you do to the primary will be sent to the secondary. The big concern is load while this occurs.

Shrinking the log makes sense, but the size of your log needs to handle the peak size between log backups with a pad. Make sure you know what this is.

For data files, be careful. You need free space in these files, and the amount of space depends on data growth as well as the maintenance you need. Calculate the space you need for at least the next 3 months and size your data file there. Then if you need to shrink, after you're done, you will need to rebuild some indexes because you will have fragmented them. I'd look at the index maintenance script from http://www.sqlfool.com.

Other thoughts: http://wp.me/p14wgJ-di