Rolando's Rules of Royal and Noble Etiquette
Knights are 'Sir Knight.' Baronets are 'my lord.' Barons are 'Your Lordship.' Earls and Marquises are usually also 'Your Lordship', though sometimes they are 'Your Excellency.' Bishops and Counts are 'Your Excellency.' Archbishops, Dukes and the Lord of Akko are 'Your Grace.' Priests are Father or Mother. Or monastics may be Brother or Sister
'My lord' is also a generic title that can used to address any noble; among freemen and peasants, linguistic drift amongst less polite society has rendered it as 'milord'.
In general, one should always use the more formal greeting when first meeting with someone at any given event. So when meeting Count Tiddlywinks of Whoville, one would greet them as "Count Whoville". Though after that they may revert to the less cumbersome Your Excellency. Or even Count Tiddlywinks.
For nobles, when one approaches a social superior, a male should bow. A female should either curtsey if wearing a dress or skirt, or bow if wearing pants. The depth of the bow depends on the difference in rank, the farther the superior's rank is above you, the deeper the obeisance. A Knight meeting a Count should bow quite deeply - possibly even kneeling in full court, while a Marquis may be just the faintest of bows at the waist.
Meanwhile, a social superior wishing to be polite may incline their head, or offer a more shallow obeisance, again depending on the difference in rank. They never truly owe anything however, especially to the peasantry and freemen, though it is generally wise to at least acknowledge a member of the Merchant League.
Other common social niceties are related to introductions, a lady should offer her hand palm downwards to a lord, who should then make the gesture of kissing it - though this does not generally entail pressing lips to the hand proper.
Two men will shake hands after bowing. Two ladies will generally leave it at the obeisance.
A slap, with a glove especially, is a challenge to a duel. As is throwing down the glove, or gauntlet if you will.