So plenty of folks are down on Hildegard because of her Dance ability being only semi-useful, but as a captain I think she shines. Her captain ability adds Research for every Prestige collect token- a bonus that really starts to stack when you begin hunting prestige, enabling Science and Follower benefits simultaneously. I admit as a team member she can be weak, but as a captain, she is great. Her pros and cons:
-A weird attack ability which is ranged but often misses. Can be useful for finishing off enemies, but don't count on it.
-A strong 2-range Impress ability which eventually gets double attack and an inaccurate Scared ability, making her Friendly attack the only really reliable move she's got. Sadly you'll run into more Impress-immune enemies in the late game, and Impress is not great as a healing ability.
-A good single-target Cheer ability for healing and buffing.
-Pitiful Armour and okay Speech Defence.

Hildegard needs bodyguards, basically. She is great at standing behind your two other team members and pelting enemies from a distance, healing when needed. Some other strategy ideas:

-Hope to get the Viking map first and try to find the Viking Drinking Horn or any other artifact/follower who gives bonuses for finishing friendly, because you will be doing that a lot.
-For flavour purposes, look for Hannah Haas as a follower, who is only 100 Renown to recruit and gives a science bonus for Friendly wins.
-Load up on Prestige-boosting lobbyists, and go for any city that gives you more.
-Team her with Emilia for a solid support Friendly character who can also heal, and cycle healing on your team.
-Nasty trick if you have Hildegard and Pederino- run Hildegard towards a large group and take out the middle target with her range 2 Impress, buffing her first with Emilia if necessary. Then send Pederino in and Dance Party to teleport him into the middle. The attack gains a boost for each adjacent target. Even better if you've researched the Excite boost in Science Preparation, leaving the survivors with -20% Speech Defence.
-Go Hungarian Fort first and grab every scrap of Prestige, then the Highlands, and then only if you are REALLY sure of yourself Transylvania. The count is Kryptonite for Friendly teams that use a lot of Excite.