1: SIMP
2: Kill Fiona without him knowing.
3: Wait a year.
4: Develop a friendship with him in that year.
5: Build on that friendship into a deeper relationship, but no romance yet.
6: Tell him on the 4th of July that you're in love with him.
7: Blame Fiona's death on the dragon after another year.
8: Watch Donkey cry as his wife is trialed for murder with all the evidence pointing at her.
9: Kill off Donkey's kids one by one and blame it on him with a note saying Shrek's kids are next.
10: SIMP