If you are targeting low competition kw's in the inner pages - a few quality social bookmarks + social signals
If you are targeting medium+ competition kw's in the inner pages - the above + 1-2 guest posts on related sites
For the home pages you should build only very high quality backlinks. Better to have fewer but quality, rather than a lot of bad links. If you have a good internal linking structure, you can always remove/redirect/etc a bad post/page but the home page will get you whole website penalized.
Hope it helps