1. Excessive un-related behavior after two warnings means punishment in the form of 1d4-2d4 points of statistic damage from one stat (str, dex, etc.)
2. These punishments are can be overthrown by the group if all (except) the DM think the punishment was unnecessary.
3. The DM rolls all spot and listen checks, other checks are on a case-by-case basis.
4. After a solid meal, and 8 hours sleep (or the racial equivalent) a character regains full hp but not temporary stat damage, diseases, spell effects or poison. All subdual damage is also healed. Note: this rule exists only to keep gameplay active and if it is not wanted by the DM for someone to regain damage, for example they're held prisoner, the DM can rule that they did not have a solid meal and a refreshing sleep.
Keep a file of all the NPCs your party have ever encountered. For a butcher or a inn-hostess this can be as simplistic as what they think about things and converse about, with no battle stats necessary.
For those DM's who want the privacy of a DM screen but not the separation from the players, try using a binder with all your pertinent information in it laid at a slight angle on the table with something propping it up. If need by you can also cut some construction paper and make a "lip" on the side of the binder facing the players to obscure their vision but not yours.