drums and cappos should be a no. if you do not know a chant, take a second and listen to it, then start singing. make up words. thats the whole idea.
Songs very rarely get started for the first time at games. If you start a song that no-one knows during a match, people don't learn it, your voice just trails off and dies. Songs get learned at groups of fans in pubs and bars - during pre-game meetings, post-game or even in the stadium at half-time. But during a match, the only songs which get sung are the ones a decent group of fans already know the words to. If you want to do spontaneous singing, the core fans must
get together to learn the words first.
Dare I say it, alcohol has a very important part in the creation of songs in the non-capo supporters culture, as being drunk makes it far, far easier to raise your voice when no-one else is singing, and then to join in with someone else when you barely know what you're singing and you're not sure the song is even that good. The decline of drinking to excess at English matches is one of the key reasons people say that the atmosphere in England is slowly going stale. It's pretty much why these days this stuff needs to be done outside of the games.