Planning a hero's skill

I don't normally recommend diversifying the skills in a hero. A hero's focus, with the exception of off-race hero, should be military. However, a hero ultimately gets 320 skill points at war level 80, and he will only need 310 skill points to master all skills in a given category. More so when a hero's specialty does not include Cav-4 and Inf combination. I hope the breakdown below helps you plan a hero's skill.

Hero with Cav-4 and Inf-5/Inf-6 specialties.
You will need to master all skills in the military tab. That leaves only 10 points for 'other uses'.
9 points in First Aid does not make sense, as a mayor without Local is rather useless. So I recommend putting the remaining 9 points in combat tab, Power Attack.

Hero with Cav-4 specialty only.
You will need 250 skill points to master the necessary skills for Cav-4. That leaves 70 points. Here, my suggestion varies depending on a hero's aptitude. If the defense aptitude is high, I'll suggest using 42 points to master Local, and he can be a standby mayor. That still leaves 28 points for some skills in combat.

Hero with Inf-6 specialty
This hero may also have Inf-5 specialty, but that won't make any difference. 217 skill points will be needed to master the necessary military skills. That leaves 103 skill points. Since Inf-6 heros don't really do well against devils or in FC, I suggest putting them in mayor position, especially at the higher levels to gain experience. Again, if the aptitude for defense is high, he will make an excellent mayor too. You will only need 73 skill points to master Local and Military Zeal. The remaining 30 points can be used in combat. If you are low on resources and intend to sit the hero in mayor most of the time, you can consider using those 30 points in other political skills.

Hero with only Inf-5 specialty
This hero require only 155 skill points to master the 5 relevant military skills. That leaves 165 skill points, more than half for other skill category. Again, I will suggest 73 points to master Local and Military Zeal, leaving 92 points for combat.