Heh, I've finished Fantasy Wars on Hard since I've played Ascension, so I don't remember clearly. Take a quest from giant near castle to rescue the witch. Don't worry, giant is superstrong, so You'll survive. With witch it'll be easier, try to explore and search for easy targets (You can decide not to fight when enemy is too strong). Look for chests with gold and (rather) authority bonus.
You'll be allright
P.S. I recall that initially I was very fond of wolves (You can hire them in a cave near first village, they are guarded though so get Yourself some army). They are cheap and very fast. Later You'd like to switch to bears (Grizzlies especially
). It's really down to You, what type of combat You like and type of units You preffer. I had all my army on Fast and above, so my medium speed hero was not needed for combat really, magic was used instead. However, there'll be a few "duel" quests, so it's good to add a little damage too, not mentioning the health (most important ).