Optional graffiti #10 is during the drive with your father. There is a poster on the seat in front of you. Interact with this poster (look then move) for the graffiti opportunity. The marker which you need can you find in the whine bottle to your left.Here is my complete video guide for all optional graffiti in Episode 1.
All optional graffiti are immediately saved. You can replay Episodes (Collector mode) to find your missing graffiti.
There are always 2 graffiti which you can spray, it doesn't matter which one you spray.00:08 - Optional Graffiti #1 (Recreational Vandalism)
00:56 - Optional Graffiti #2 (I See U Saw)
01:34 - Optional Graffiti #3 (The Last Unicorn)
02:22 - Optional Graffiti #4 (Home Unimprovement)
03:44 - Optional Graffiti #5 (Rock Idol)
04:36 - Optional Graffiti #6 (Dramatis Personae)
05:23 - Optional Graffiti #7 (Mulligan Stew)
06:36 - Optional Graffiti #8 (Pioneer Spirit)
07:20 - Optional Graffiti #9 (Face Your Anger)
08:10 - Optional Graffiti #10 (Lucid Writing)