I start with a large top view of the object in TESCS. Then using GIMP I make a screen capture.
An explanation of the menu options:
Bestand = File
Importeren = Import
Schermafdruk = Screen Print
Using the Fuzzy Select or Magic Wand Tool I remove the grey background.
Because the final icon is only 32*32 pixels in size, you have to use the area as efficient as possible. Therefore I rotated the dagger 45 degrees.
Applying an alpha channel for transparancy
To avoid your icon being displayed in an ugly black square, you have to add an alpha channel with transparancy information. This is how you do that using GIMP.
Right click on the layer of the image, select "Add layer mask" (Laagmasker toevoegen).
Then select "Alpha channel from layer" (Alphakanaal van laag)
You should get something like this:
Beside your image a black-and-white copy appears.
To apply the new layer right click, select "Apply layer mask" (Laagmasker toepassen)
The black-and-white image vanishes. Finally I have to resize the image to 32*32 pixels. Save it as either TGA or DDS, done!