Quality control when exporting graphics into JPG

In the help file for Jpeg, there is the option to control the quality of the export. The default value of CompressionLevel is 0.25. Decreasing this will help to give better jpegs. The other thing you can do is to set the ImageSize larger. This creates a larger picture that gets compressed into jpeg, again improving the resolution. So together, these are:

pl1 = ListPlot3D[lst,PlotRange -> All,ColorFunction -> Function[{x, y, z},  
     Hue[0.9 z + 0.1]], ImageSize->1000]
Export[NotebookDirectory[] <> "exportTrial.jpg", pl1, "JPG", "CompressionLevel"->0]

I think you may find that increasing the resolution like this also fixes your Glow problem.

It is not about ImageSize, is ImageResolution what you are looking for.

Just do the following,

 YOURdpi=2000;
 Export["mygraph.png", ImageResolution->YOURdpi];