The basic rules of web site accessibility apply equally to any web site being viewed on a touch device or small browser.
- Avoid tables
Small screen browsers do a great job at scaling and zooming your site to fit the device but as soon as you use tables for your layout they start to have problems. Check out a table based site such as the Joomla forums to see what I mean. - Avoid adjacent links
When you're using a mouse it is not too hard to correctly select the right link from a group of links but try doing that with fat fingers. All links should be rendered clearly with separation between the links - Check any drop down menus and mouseover effects
When browsing with your fingers its not possible to hover over an item. If you need to hover over the top level of your menu to expand then your viewers won't be able to. One option here is to ensure that all top level menu items are real links (even #).