My guide to using heroes:
1. Unlock alot of skills. Heroes can use all non-PvE-Only and non-titled dependent skills you've unlocked. I try to get 10,000 faction a week from ABing and get alot of Balth faction along with Luxon faction. If you don't have Factions just do Random Arenas a few times a week. Using Balth faction to unlock skills saves you loads of money and time.
2. Learn to use the flag. Heroes will follow you wherever you go. So if you want to pull a mob you need to use the flag. It will keep you AND your heroes alive.
3. Be aware of your heroes' skillbars. I used to get mad when Acolyte Sosuke would run into battle instead nuking at a nice, safe distance. But I recently realized his bar was filled with skills like [skill=text]Inferno[/skill] and [skill=text]Flame Djinn's Haste[/skill].

So make sure your heroes' skills reflect your goals.
4. Different areas require different builds. Its pointless to have skills that are useless in that particular area. Example, don't give a Warrior hero Gash or a bring Minion Master in an area with no fleshy creatures. So have a few builds for each profession. GuildWiki builds are just fine for heroes. *lol*
5. Don't spend any money on them if you can help it. Most people just leave their heroes with whatever weapons they come with or give them drops. The same is true for runes. The only runes I've ever bought for a Hero are Superior Absorbtion and Superior Divine Favor and only because I use them alot. Note: You can give heroes weapons that are customized for you. The GoTY and the GWEN preorder items are a good example.