Losslessly compress images and hack to download splash image sooner, per PageSpeed.
Remove <br/> tags in favor of something _slightly_ more semantic
Increase tap target size for post index and footer links, per PageSpeed. Also improve post index semantics.

Because the post index displays like a table, the best display option for truly empty space between rows is, unfortunately, a spacer row in the markup. Lengthy discussion of options here: http://stackoverflow.com/questions/351058/space-between-two-rows-in-a-table