Inkscape is the program I use to design vinyl and other projects. It's confusing and hard to use, but it's free. 

General Drawing Tips

• Erasing: can draw box over piece want to cut out
• Hold shift and select both items
• Path difference
• Can use guideline for placement
• Path union - melds together
• Control shift makes circle symmetrical 
• Control shift f brings up fill panel. Can mark no fill, and stroke panel for outline. 
• If borders are the same, can Align and use center to align 
• Path —> Outset thickens lines

Text

1. Need to press object to path!
2. Then Path —> Union

Tips

• Text —> Put on Path makes text follow shape you have selected
• Path —> Object to Path makes it so you can delete underlying shape

 Outline Object

1. Drag and drop file (choose embed)
2. Path —> Trace bitmap
1. Single scan: centerline tracing
2. Make sure the image is selected and press update
3. Use the node tool to delete any artifacts that were picked up (also I changed the color to black).
4. Go to view -> display mode -> outline
5. Path -> stroke to path. If you want it thicker, go to fill and stroke -> stroke style -> and change the width
6. Go to view -> display mode -> normal
7. Save as plain SVG file

Fill Object

1. Duplicate
2. Path -> break apart
3. Grab just the outline piece and move over

Writing Fonts

1. Put in text
2. Path —> Object to Path
3. View —> Outline 
4. Draw Bezier Curve
5. Combine multiple strokes
6. Auto smooth
7. Stroke at one 
8. Pass combine at end

Create a Cutout (like for one color vinyl)

1. Drag and drop file (choose embed)
2. Path —> Trace bitmap
3. Multiple scan: change scans to 2
4. Select colors
5. Check smooth
6. Uncheck Stack
7. Check remove background
8. Make sure the image is selected and press update
9. Press node box and delete any pixels that were accidentally picked up
10. Then go to Path —> Simplify
11. Path —> Union
12. Save as plain SVG file

Multiple layer vinyl

1. Drag and drop file (choose embed)
2. Path —> Trace bitmap
1. Multiple scan: change scans to how many colors you have 
2. Select colors
3. Uncheck smooth
4. Check Stack
5. Check remove background
3. Make sure the image is selected and press update
4. Then go to Object —> Ungroup
5. Don’t need the different color layers, instead:
1. Fill in image layers with paint
2. Select all pieces and Path —> Combine
3. Do this for each layer 
6. For base layer, fill in the whole image in base color. Go to Path —> Break Apart; then Path —> Union
7. Select entire image, then Object —> Group
8. Save as plain SVG file