Biology is mostly learning things by heart, like definitions, diagrams, experiments, etc. It isn't too difficult, you just need to focus on memorising things. Some chapters you will like more than others and some will be easier than others but my main tips are make sure you learn definitions perfectly because they're very strict about them in exams and practice exam questions.
If you enjoy chemistry and if you have a good teacher, then it will be much easier for you. From my experience, the first 6-7 chapters you learn will be quite easy and you shouldn't have too many problems with them. You learn definitions, experiements and theories. You'll find some chapters really hard too. For me it's moles and organic chemistry but as long as you take time to understand those topics you should be grand!
There are lots of helpful videos and notes online. Use those and practice as many exam questions as you can. It really saved me in fifth year.
Good luck! :)