I would say choosing AQA as the exam board is your best bet, as there are the most resources online for it. Then, there is a plethora of videos that you could watch that will explain everything step-by-step from teachers and tutors in order to maximise your marks. You might struggle to mark your own work because of bias, to which I would suggest a tutor, but if the aim is to pass, then looking at exemplars and taking on tips to produce the best work is what I would recommend.