If you’re just looking for general advice then:
Don’t send out blanket CVs, it’s always worth tailoring them to the requirements of the job you’re applying for. Rather than just explaining what you’ve done in the past, you’ll also need to elaborate on what you’ve learned and gained from it. Make it as easy as possible for the person reading your CV to identify what you’d be bringing to the job.
If you’re applying for a job involving customer service and don’t have a lot of experience in the field then it might be worth doing some voluntary work in a charity shop.
Take the time to prepare for your interview with a friend or relative beforehand. You can expect to be asked questions along the lines of “tell me about a situation where you worked as part of a team” and it can be worth having prepared a few responses ahead of time. It’s also probably better to be too smart than too casual.
Other than that good luck! Hope you find what you’re looking for soon.