How sure are you?
Very first thing you need to make sure that you took the decision after careful consideration. Do you really want to transfer university? Do you really need it. No doubt it is a big step, so you might find that changing quite challenging.
Try to discuss it with as many people as possible. You'll need your parents on your side, and if you need a reference from your tutor then it would help if they knew you wanted to leave.
Why are you changing university?
Your reasons will be personal or change of subjects to you, Or simply other university got better reputation and facilities the subject you studying. So I'm not going to try and discuss them all here. But you do need to think about why you want to leave your current university, and why you think that this new one will be better.
Remember that not so long ago, you were convinced you wanted to come to this university. Even if it was your insurance choice or you came through Clearing, you still made the decision to go there. You need to be sure that you're not just making the same mistake again, and that you will be happy once you've changed.
How to change university
Once you have decided which university and course you want to change to, you need to contact that university. Don’t forget to do research about that university and reputation of specific faculty. Do not rush one this stage, because you want to make a good impression to your new University.
Phone/email the university, and ask who you would need to contact. You want to email a specific person: probably the admissions tutor for that course. Don't just email the general enquiries address.
In your email, write exactly what course you're doing now and what course you want to change to. It would help to include your A Level grades, any work experience, and why you want to change. But this is your application, so make it individual to you.
Wait for them to get back to you. This may take a while, but if you haven't heard in a week or so it might be an idea to phone them to ask about it.
Once they've agreed, you will need to apply through UCAS. If you're applying for a second year transfer, then don't worry about the deadline as the UCAS application is just a formality, but you will need to ensure you put the "point of entry" as 2.
From here, the procedure is pretty much the same as it was the first time!
Make sure that you notify everyone at your current university.
After the Confirmation:
After getting the confirmation you need to sort out accommodation to stay if the location far from your home. You need to move your belongings to new university. You need to find a reliable student shipping company to ship extra luggage to new place. Make sure shipping company cover international student shipping if your university is located abroad to avoid disappointment. Some companies offer free collection and storage which could save you some money.