To play creation well, you need to decide her role pre-game to adjust her traits and genes accordingly, because her stats level up like other units. Then, earn money early and keep her lvl 1 until you've corrupted enough units to change her lvlType from average to something more fitting of that role (early slime tree).
Then you can start to breed/recruit a team and level up creation with worthwhile stats. Her power of creation is amazing to complete all "breeding" type quests once you've farmed enough base genes through rituals. It'll also help endgame to patch up whatever ritual you haven't done yet with easy access to breeding those species.
For combat, think about your action economy. Characters with the "agile" trait, and the focus spell can break the action economy by getting 2ap always. Spells like "jump" and "blink" let you move a bit without spending your precious AP. Charge-style attacks and spells let you move and attack at the same time. That's the kind of thing that will you take over fights from turn 1 and stomp your enemies. Shields (aegis, protect and teleport with mag>7) on your units engaging multiple enemies at once by themselves is very worth it too. If you buy into 1-timers, ice spirits can stun every enemy once.
For training i'll assume it's level ups, you've safe options, and you've got combat. Your MC can trade 30min and 10 energy for 10 xp (15when Aila is here) in the training room. Aila can train your units two times a day with relation >20, 50xp for 300 gold each time. You can craft XP potions by farming craft components (3 different recipes, some species produce 1 item daily, it's written in "others" on their page, needs morale>25).
And you can fight. If you fear they might die in portals, you can put units in reserve mode so they don't participate in combat 25%exp penalty though).
There you go