The best place to start is by looking at same or similar items currently listed on ebay, or recently sold by selecting completed listings in search resulst. That will give you an idea of the kind of market there is for those items. what kind of listing format is the most popular and/or successful, what kind of prices are achieved and so on.
Aside from that, the general basics are mostly common sense ones 🙂 i.e. Understand your responsibilities and/or obligations for listing on ebay and any payment methods you use, take great photos, show any flaws in close up, have detailed but succint descriptions that don't downplay flaws, have reasonable terms of sale (if any are used), and quote reasonable P&H.
