We all know that you can choose to digitize a design either automatically, semi-automatically or choose to tackle the design manually, but did you know that there are a lot more decisions, some obvious and some a little more subtle. I figured that I would jot some down, and share them with you.
Here they are in no particular order.

Minimizing the details
You can only put so much detail in a design before it becomes indistinguishable.
Also including too many details will also cause thread breaks and bird nesting, because there is a limit as to how many stitches can be placed in any given area.
To pare down details try tracing the details on tracing paper with a pencil. The width of an unsharpened pencil will roughly equal the width of a bean stitch.
In the very least turn 3-D view on and view it at 1:1 ratio before you sew it out, if the detail looks good you are fairly safe that the design will also. Another thing to look for is short stitches, they are also a source of thread breaks.

Overcoming fabric types,textures and patterns
Use underlay to stabilize the design, always start with an overall running stitch underlay on stretch or slippery fabrics.

To use underlay to flatten the texture of knits such as pique, place a zig zag underlay under satins and a lattice underlay under fills.
Also use lattice underlay under fills when sewing on velvet, corduroy, and fleece.
Use edge walk running stitches under columns when sewing on twill
When sewing on caps, start in the middle and work our way out alternately from side to side. Place your underlay as you digitize each piece.
Overlapping
Always overlap the first color and then place the second color on the dividing line. If you rely on pull compensation to make your stitches overlap you lose control of the exact point where they meet.
Blending
You can either choose to blend colors by using a gradient density or by overlapping fills or satin stitches.
When using either of these methods you want to keep the stitches as close to parallel as possible, so they will blend and not separate.
Lettering for foam
By placing satin stitch at the end of each column, you can be assured that the ends of the column stitches will be perforated and the edges will be hidden.
The few random thoughts were meant to get you to think about why some embroidery problems occur and to help cut them off at the pass.