Yuo want to start with the obvious bits, like at the moment i just carry a multi tool, two 15mm wrenchs (ones a multi wrench though) the things for lifting tyres from rims, an army of zip ties but i wnt to buy a bb remover, freewheel tool a bike stand, a bleed kit, one of those things for trueing wheels! Buying some of those things would be a step in the right direction!