Consider Geography or History - known as Humanities subjects - as these are considered to be facilitating subjects e.g. subjects that are most commonly required or preferred by universities to get on to a range of degree courses if that is your intention.
Choose subjects that you enjoy. If you enjoy the subject, you will put more time and effort into it and the more time and effort you put in, the more successful you will become.
Choose subjects that you are good at. You need to gain as many high grades/points as possible.
If you have a definite career in mind, choose subjects that will best support your career route. However, remember that however keen you are on any particular career or job now, you may possibly change your mind before you leave school. Many people also change their career during their working life. Your choice of subjects must not limit you to just one type of career. If you have no definite career in mind choose what you are good at, what you like doing and what will give you a good spread of subjects. Many subjects can be picked up at A-Level or beyond without earlier study.
Do find out everything that you can about the subject before you choose it. Once you have started a subject we expect you to stick with it for the full two years.
Listen to advice given to you in subject talks in assemblies.
Talk to your parents, subject teachers and Year 10/11 students.

Don’t:

Try to get in to the same groups as your friends; it probably won’t happen.
Choose a subject because of the teacher; teachers change.
Just go on your experience of Years 7 to 9; look at what each subject has to offer in Year 10 and 11: it may be different.
Narrow down your options too much; you may change your mind about what you like and what you want to do in the future.