Kenyaxo - you could try local kennels and cattery's
or you could also try local leisure centre's - they can be fantastic for someone your age as once you get a foot in the door and show willing to have a go at the various roles on offer, as soon as you turn 16 they will more than likely offer you training such as life guarding or sports coaching for free - great for your CV when/ if applying to uni.
How about contacting local childrens indoor play areas - they have a high turn over of staff (generally) as staff start, stay for a year or so, then go off to uni or college - so they will probably have a job for you.
What you need to think of is what kind of job do you want? Do you want to work with the public? Or Kids? or sport? then google local business's with your key words and drop by with a CV and a smile - be enthusiastic and polite to prospective employers you meet - you'd be amazed how much of a difference that makes, especially as your CV will be understandably a bit thin to start with.
Good Luck! :-)