Books on MIDI editing, sequencing etc..

Here's some tips that come to mind

1) make sure to have correct Velocity - you already mentioned this one

2) Expression (cc11) - make sure your chords/notes dont 'pop' in and out unnaturally..zooming in and doing a fade in and out in the PRV can make a difference in realism. (Especially Choirs)  Depending on your sample library you might want to work the expression date heavily, even on sustained notes for more realism

3) Crossfades - Some libraries have crossfades while others you will have to make your own.  For instance a horn swell.  This will involve not only volume but also velocity (the timbre changes as it swells).  Without a crossfade patch (or a swell sample) theres no way to change the Timbre one a single note once it is 'played'.  So here is a workaround.
    -Track 1 add note with low velocity
    -Track2 double same note with high velocity.
     -You will then crossfade the two tracks using expression (or volume data).  Make the low velocity go from silent to 1/2 through the note the fade it out while the high velocity note fades in 1/2 way through the note and takes it until the finish.

-Experiment with mixing your runs using legatto and stacatto samples together.  For instance you can add a stacatto hit for the first and last note while keeping the middle notes legatto.  This can add some realism in the right situations.

Expression (CC11) - is volume.  However we use expression instead of volume (CC7) because we like to save the Volume for our overall track volume. 

Velocity - Effects how 'hard' the instrument is played and thus will effect the timbre.  Like hitting a drum soft or hard.

Layering solo instruments with sections can add some depth.  IE:  A solo violin mixed at appropriate level with the 'violin section' ..a solo voice with the choir ..etc etc.    It is also common to mix a real solo instrument with the samples.  The samples will fill out the sound while the solo instrument will add the realism.  This is common in TV where they typically have lower budgets and cannot hire a 70 piece string section

Most important is - learn your sample libraries as each one will have different strengths.  Some sample libraries assign different CC (Continous Controller) data to different numbers. It's going to be important to read the manual for the libraries.

Going into Tempo view and making slight tempo changes during your piece can have decent results.

If your mixing orchestral music I would suggest setting up a template that includes reverb for each section of the orchestra with the appropriate reverb settings (IE placing the drums in back and the violins up front)  This is a time saver.


Hopefully you found something usefull in here.  Midi mock ups are an artform in themselves and require ALOT of time spent with your sample library(s) of choice.