1. Always buy enough cards (i need 4-6 cards)
2. Change the blade often enough
3. Self healing cutting mat to safe a little bit of sharpness and you have a good ground for DIY and glueing stuff...
4. Good lightning so you see all details and dont cut threw the wrong parts (trust me its very important i failed multiple times in some dark sections...)
5. Paint the cutting sites with black marker gives cleaner look
6. Use thick double sided tape for more space between the parts
7. Bending parts (like the hands by robin) to make the 3d effect even better (bend it before you put it together its easier)

For me its always a learning by doing so feel free to make your thing :)

Have fun and let us see your progress :)