You'll be able to get a job if you want one. You may not need one, but it'll supplement your income. You don't need to organise it before you start because there are lots on offer, but do it when you want.
You could get one of the various jobs on campus, or one in the local area and city. There's also a jobs fair in Welcome Week, on Tuesday 24th, 11am-4pm in the Great Hall.
There are lots of jobs that don't require too many hours, and would allow you to stop working during the holidays. It wouldn't be a negative impact on your first year depending on the course expectations.
To get a job, there are various services:
JobZone is jobs in the local area, and in the Guild of Students. It's office is based on the ground floor in the Guild.
Worklink is the jobs on campus (but not in the Guild). Their office is alongside JobZone's.
Careers Network is the source of funding, advice for internships, and eventually, further study or graduate jobs/schemes. They do the standard CV and advice things, as well as careers fairs, workshops and employer events.
Check the Social Media page for their facebook/twitter accounts, as well as the course specific Careers Network accounts.
There are numerous external companies that promote jobs as well, who are obviously motivated by profit and not tailored to Birmingham students, whereas the services mentioned are here are primarily concerned with assisting you.
If you're sending out 50+ CVs and not getting anywhere, then there's something more you can be doing, so get an appointment to get some advice and get it checked. You can do that at both the JobZone and the Careers Network, although the JobZone will likely be more relevant for a part-time job CV.