Rule 6: Learn some dates
This one may seem obvious, but I mention it because it does really come in handy. As I've had occasion to mention on the podcast I don't have a very good head for dates, so I try to remember some specific ones as landmarks -- like the death dates of significant philosophers, and then you can at least get a vague idea when another philosopher is by knowing whether they are earlier or later than that philosopher. (A good one, as I mentioned in the relevant episode, is Socrates' death date of 399 BC, because you can work backward to know when the Presocratics were and forward for Plato and Aristotle.) It's also a good idea to learn some other non-philosophical dates, to help with knowing what the context of the philosophers' work was. Cf. rule 4.
While I'm on this subject, don't forget the timelines here on the website (in the menu above) which give you the dates for all the philosophers I've mentioned on the podcasts thus far, with links to the episodes where they are covered.