I have not used Paint.NET for awhile but mirroring should be from menu bar image->mirror or flip.
Glow effect is included in versions 2.7 and higher. ( Or use BlendModes+ glow, itīs in the pinned plugins)
Selection tools are the horror of Paint.NET in my opinion. It has no bezier or magnetic lasso tool which makes amorphous selections a hard task.
You can use the normal lasso tool in "add to selection" mode, still quite hard. Or create 1 additional layer, paint over the area You wish to select, select with wand and crop.
BUT before that I suggest You go to the Paint.NET forums, download & install the pinned plugins. They add much functions, probably some enhanced selection tools also.
Itīs quite a task to go through all the post and but worth it.
http://forums.getpaint.net/index.php?/foru...ublishing-only/