For the US, an excellent starting point would be the Coast Guard's Aids to Navigation brochure; it explains all of the markers you are likely to encounter and provides a brief overview of the "rules of the road". The Coast Guard's Navigation Rules Online is an unofficial merger of the International Regulations for Preventing Collisions at Sea (COLREGS) and the Inland Navigation Rules. (The occasional differences are listed side-by-side when they appear.)
In questions of right-of-way, you will either be the "stand on" (obligated to continue your current course and speed) or the "give way" (obligated to yield) vessel. However, you shouldn't think this confers a "right": both parties have an obligation to avoid collisions. This means that should a collision happen, you can usually assume both parties will be considered at fault (though to a varying extent). Which vessel is which depends on many things: is it under power, under sail, constrained in a narrow channel, etc. In general the vessel with the least maneuverability is the "stand on" vessel. Kayaks are not really called out in the Navigation Rules, but a Coast Guard FAQ supposedly (the direct link is broken) said the following:
Where do Kayaks and Canoes fit into the Navigation Rules? Neither the International nor Inland Navigation Rules address "kayaks" or "canoes," per se, except in regard to "vessels under oars" in Rule 25 regarding lights. One could infer that a "vessel under oars" should be treated as a "sailing vessel" since it is permitted to display the same lights as one, but, ultimately the issue of whom "gives way" would fall to what would be "required by the ordinary practice of seamen, or by the special circumstances of the case" (Rule 2).”
Per Rule 18 (establishing the "pecking order") a power boat should probably keep out of your way, but per Rules 9 and 10 you must not impede traffic in designated traffic lanes and channels. Also, be aware that large vessels (like container ships) move deceptively fast; you want to stay well clear of them!
I suggest obtaining charts for your area in case there are any special exclusion zones. They will also show the COLREGS Demarcation Lines, indicating where the Inland Rules take over. Between the charts and the brochure linked above you should be able to identify traffic lanes and channels in your area.