To turn keyboard shortcuts on, go to Mail Settings by clicking on the Cog and choosing Settings, then in the General tab find Keyboard Shortcuts and select Keyboard shortcuts on. Then try out some of the shortcuts below.
||Compose new message
||Start a new search (cursor jumps to search box)
|With an email selected (by tick box) or open:
||Open Label menu
||Open Move To menu
||Report as Spam
||Move to Bin
There are other keyboard shortcuts you may want to try, from your Gmail inbox click Shift-? to bring up the whole list.