MUNINN'S PROFILE

Those are some pretty good tips (I'd extend the first one to all encounters in general), although I'd say that the third one should be taken in moderation. Half-hour random encounters might alienate the player, but nobody wants to be dragged away from the map for an encounter that's going to be finished in less than 2 rounds of battle (aside from early-game training battles, I suppose). In general, there should be an inverse relationship between encounter frequency and encounter length, but going too far toward either extreme becomes unworkable. (ie. hit-attack-once-and-everythings-dead encounters every 3 steps, or a 20-minute encounter once every 5 rooms).

The "Warning Posts" idea might also be less-than-effective at first, as well. I seem to recall once being told that in Zelda games (but being information that could be extended into rpgs), there are two major types of NPC dialog: "You should check out location X" (which means go to location X), and "location X is a dangerous place, you shouldn't go there" (which also means go to location X). Players might eventually get the idea, but at first they'll probably hear "It's a dangerous place that can only survived by a 'Strong Hero'", where "Strong" is defined as "whatever level the PCs are when they arrive at that location".