First record at least one MIDI track, then record the audio. If on the other 
hand you record the audio first, there is no clock reference resulting in 
syncing discrepancies between MIDI and audio. You may add more MIDI tracks 
later as needed.

If a song starts with a vocal instead of a MIDI instrument, use a count off,
then leave space for the audio track with the amount of measures needed for 
the intro.

--------------------------------------------------------------------------
If MIDI & audio drift apart after a couple of minutes or so, 

In DOP:
------- 
 1) Options | Digital Audio Port Setup | Options, check 'Enable Wave Sync'
 2) In your Dop.ini file, 'Options' section, find the line:
    UseMIDITimeStamps=1  and change the value from 1 to 0 so that it reads:
    UseMIDITimeStamps=0
    If you cannot find this line, just create it anywhere under the Options 
    section like this:
    UseMIDITimeStamps=0

In Cakewalk 9.X:
----------------
Options -> Audio -> Device Profiles -> "Use wave out position for timing" 
must be used.
      
____________________________________________________________________________