A couple of things can help a lot when trying to use a touch screen.
I have found setting the default system text size to %125 improves the general usability
Its very useful to be able to change screen resolutions quickly. I uses HRC - Hotkey Resolution Changer to flick between three screen resolutions instantly when I am using a keyboard.
When I am just using the tablet by itself I use the Windows Magnifier. This in particular has changed the whole way I work. For example, if I am setting an envelope I can zoom in until only the controls I am focusing on are visible.
So a Rapture envelope window ends up being 350mm wide and 200mm high. Might look stupid but it makes tweaking a whole lot more satisfying than pecking away with that antiquated monstrosity known as a mouse.
The whole way I look at the plugin interfaces has changed. I used to think that the retro interfaces with their knobs and switches were a pointless distraction which might lead me to mix visually rather than use my earsw.
One of my favourite features in Project 5 was the way you could assign any controls to bars in the inspector and get rid of custom gui's completely
Now I zoom right in just to what I need.
Because there in no right mouse click in Sonar touch, the last piece of software I use is a app called Touchmousepoint. Wothout it you cant really do much with sonar on a tablet. Its not ideal though.