4. Use of multiple display monitors can streamline one's work flow. 
 
5. Set a Keybinding for reset of clipping indicators is helpful. Y is a good keybinding for it.
 
6. Access the Sonar forum for help 24 7.
 

Keybindings are your friend. The most useful and basic keybindings for easily accessing all the controls you need are: D = Dock, I = Inspector and B = Browser.

To quickly and accurately set an initial tempo for a new project before recording:
 
- Disable Stop at Project End in Track View Options if it isn't already so you can run the transport in an empty project.
- Start playback with no click sounding, count off several measures in your head, and stop the transport on the next downbeat.
- Shift+M to open Set Measure/Beat At Now, enter that measure and beat and Okay.
- SONAR will automatically reset the initial tempo to make the specified timeline beat fall on the absolute Now time where you stopped the transport.
 
This works especially well when setting a tempo for someone else. You can just ask them to count, clap or play a steady tempo on an instrument, and start/stop the transport on their count.
 
Note that SONAR will also insert a matching tempo at the beat you set. This extra tempo map entry won't matter unless you want to change the initial tempo (e.g. to round it to the nearest whole number). In that case, you'll want to delete the extra entry (Views > Tempo). 
 
 
 

Post count matters not.

Post count matters not.
 
Edit: Perfect yet totally unintentional looping FTW!

When using input-monitored hardware synths in a project, group the Solo buttons of the corresponding MIDI and audio tracks to ensure the instrument keeps sounding when either track is soloed.
 

Perhaps someone can word this better for me. 
 
Need more effect on a specific phrase? Put desired effect on a bus and send it to your track. Use automation to control the send level at specific points. Isolate the word, phrase, or any part you want by clicking a couple nodes at each end. Click additionally needed nodes in between to adjust to your liking. (I usually use this for reverb and echo/delays)

Mine is a very simple tip:-
 
F11

8. Instrument Definitions can be searched by a right click on the patch widget in the Inspector or the track header.
 
9. Try loading Standard MIDI files via Sonar's  file open menu. Import will strip all tempo information to match the current project.
 
 
10. Freeze can be used to lower the CPU usage on tracks with a lot of plugins active.
 

11. Set up a master buss and have all tracks and or buses go through it. Use sub buses to keep like instruments and vocals together. 
 
12. When exporting an entire mix use the master buss as the sole source.
 
13. Use buss colors to identify tracks feeding them.