Hi freaya and welcome to the forums.
Please read the sticky threads at the top of this forum, and any other threads which interest you. These will provide you with a great deal of information. I would also recommend you download and read Google's Search Engine Optimization Starter Guide. After that, if you still have any specific questions, then please feel free to post again. Meanwhile, I am closing this thread, as your question is too vague to attract any meaningful answers.