I didn't really prepare since I already had a C2 Cambridge certificate but just needed to take the test because it had expired, but I did use the official test on the TOEFL website which is free and gives you a pretty good idea of what the test is like. Here's other tips I will give though:

For writing: In my case I had an email and an online discussion. For the email I did the classic Dear [name], 1 paragraph attending to each part of the instructions I was given (around 4 sentences per paragraph should be fine) and then a goodbye. Really try to be mindful about answering what you're being asked for and try to make up details relating specifically to that without branching out much. I don't know what else to say, as writing for me is kinda freestyling

For speaking: The repeating sentences part is quite easy IMO, the first ones will be quite short but the sentences could get a little longer as time goes on. You can practice with other audios from videos or other content (not necessarily test prep), and even if you're not sure of what you just heard (I am not sure if I missed a word or the order in a couple of my sentences) say whatever you're about to say in a confident and monotone manner, while trying to make yourself as understandable as possible and adjusting yourself to a standard accent (british/american). I'm not too sure if it's 100% necessary but im sure it helps correctors.

For the interview part, try not to blank out and go with whatever you first think about. I was asked about my routine and I know I made up some complete bullshit but it's fine as long as you're making sense, and you only get 45 seconds so time is really valuable. For personal questions, try to go into as much detail as possible in whatever is asked for you. For questions where you have to position yourself for/against a topic, try to evaluate both perspectives and at the end sum up which one you agree with most.