Cut the fruit into small cubes and combine in a jug with the wine and the rum.
Stir and keep the mixture in the fridge for at least 3 hours to chill.
Add the banana just before serving and top up with soda or sprite.
Notes
Your choice of soda or sprite will depend on how sweet the fruit is and how much it has flavoured the wine already.
If you need to speed up the process and serve the sangria immediately, you can also add some sugar syrup or peach liqueur to balance the acidity of the wine.