Xcode provides many keyboard shortcuts that can save our lot of time.
Here is a list of few shortcuts that you might want to try out:

cmd+shift+o Open quickly
ctrl+cmd+left arrow Go Back
ctrl+cmd+right arrow Go Forward
ctrl+cmd+up Jump to Next Counterpart
ctrl+cmd+up Jump to Previous Counterpart

cmd+r Run
cmd+b Build
cmd+. Stop
cmd+shift+k Clean project
cmd+i Profile

cmd+0 Hide navigator
cmd+1 Show project navigator
cmd+2 Show symbol navigator
cmd+3 Show find navigator
cmd+4 Show issue navigator
cmd+5 Show test navigator
cmd+6 Show debug navigator
cmd+7 Show breakpoint navigator
cmd+8 Show log navigator

cmd+k Clear log (debug area)
cmd+shift+y Show/hide log (debug area)

ctrl+6 Show items list in current file/document
ctrl+5 Show files list in current group
ctrl+4 Show top level items
ctrl+3 Show next history
ctrl+2 Show previous history
ctrl+1 Show related items

cmd+l Go to line number
cmd+f Find in file
cmd+shift+f Find in project
cmd+alt+f Find and replace
cmd+g Find next
cmd+shift+g Find previous

cmd+n New file
cmd+shift+n New project

cmd+alt+1 Show file inspector
cmd+alt+2 Show quick help inspector
cmd+alt+3 Show identity inspector (for xib only)
cmd+alt+4 Show attribute inspector (for xib only)
cmd+alt+5 Show size inspector (for xib only)
cmd+alt+6 Show connections inspector (for xib only)
cmd+alt+0 Hide utilities