Gosh! I've recently been asked quite a bit by friends starting PhD's whether I have any tips to pass on. I'd probably say that one of the essentials is to make sure you have a good support network - family, friends, colleagues, this forum. A PhD is an emotional rollercoaster ride - so you need people who can bring you up when you're feeling low, and some you can share your highs with! For the PhD itself, difficult to know where to start - I'm a bookaholic & use 'How to write a thesis' by Rowena Murray - directed to the writing side of a PhD, there are also others like 'How to get a PhD' but I don't have a copy of this so I don't know if it's any good. I can also recommend http://www.phdcomics.com/comics.php to keep you laughing through the process