you need good farmer heroes. To level their abilities better don't level their star up.
level them to the max level of each "star" and start raising their abilities. Otherwise you raise their abilities random, which is sometimes frustating.
Scopio is a good attacker, jean a really good support. Try to get lohar or boudicca for barbarians.
Green heroes doesn't need to be leveled asap ( they are really weak ). Heroes with defend abilities arenn't that strong ( Hermann for example ).
Depending on your plans try to raise resource buildings and hospitals first.
be really careful in killevent time. build up many tier 1 siege weapons ( fastest units for collecting goods ).
That was it for the moment. Have fun stay strong. Keep going.