Piano piano piano. The piano is honestly your best friend when writing for any genre. Personally I sit down at the piano without anything in front of me and just start coming up with ideas. It's way easier to sit down and write an entire tune and then (using a MIDI keyboard) translate that into MIDI to work from your DAW. Even if you don't have a piano, it's always good to have some kind of instrument around to help with hearing new ideas and experimenting with your song.