Having a website being registered with your country tax and business registration, be on google my business then online marketing having a proper booking form, cancel/refund policy, managing booking and clients, building connection locally with school kindergarten music association or any local association. Also being very specialised is in my opinion a must but other might have different view about this… consider not making any money for the first few years being a reality also you will be competing against many others like yourself and sometime against the big production and studio, your pricing will dictate the quality of your client don’t be cheap even you are not booking anyone this will only bring the kind of client you don’t want to deal with … think also of your potential client and why they would spend money on a photography session or photo, you have to be able to sell yourself in a extremely subtle way …