How can I easily select "Cancel" on my Z3?

I love the BB form factor - until I got my Z3. I have a love hate relationship with this device after only one day - a 4.7 inch Samsung almost has the same screen size and security apart I am struggling to keep the Z3 and would probably want to revert to a 9900 sized device with a trackball and that is easy to navigate and control. How in the world can I press "Cancel" at the top left of the screen, and perform a bunch of other menu commands and functions without holding this device in two hands? Are there any shortcuts?

Also am I able to make the suggested words in the keyboard frets any larger?

Thank you.

A BB Addit

In what situations are you trying to press cancel in the top left? can you provide any examples? what screens? what apps? so we can try to see if there's another method to acomplish that task for you?