Have dinner with your friend and help her draw up a checklist.
This advise is taken from my own personal experience doing exactly this. And it did help the person I was helping significantly, though as part if it, we also created a character to suit their requirements.
Checklists are an amazing technology that are astonishingly underrated by many people. Functionally, the checklist's role is to enable pre-cognition outside the heat of the moment. With any sort of complexity problems, a checklist is a good way to reduce the granularity of the problem such that a player can concentrate on the novel elements.
So, while I made a checklist for my epic character, with a list of the actions I would take if this or that were true, or on the first turn, the point of the checklist is not to strictly adhere to the thing, but to reduce the need to think about all of the things on the list.
When having this conversation, first discuss common "patterns" in combat. Figure out common situations that she remembers from game. While there are plenty of theoretical situations, it's more important when doing this to let the cognition and inspiration of tactics come from the individual. Just like with making a cheat sheet, the act of making the thing is more important than the thing itself.
After listing all of the common situations that she can remember, work through sample outcomes with her in whatever way suits you two best. (My preference is for statistical analysis, but then I'm very special. One of the simpler ways is to play it through a few times, alternating sides and talking through your decision.)
After each finishes, let her work out a checklist of "if this situation is happening try for X,Y,Z" Then, after a set of checklists are done, let her employ them in game. After she does, make sure to debrief her after game (written or oral, since there is some literature that suggests a written debrief has great learning potential) and talk through what went right, what went wrong, and what needs to change in the lists.
Enlist the help of your Creative Player to involve the others.
CP is very creative and he is clearly motivated with the game. Explain him you have to focus on the other players and use hooks for them, so he could help you creating those hooks, being in character (he ask the other PCs favours that involve them) or totally out of character (he makes up that an old enemy is looking for one of the PCs).
Ideally, each player would create his own hooks, but some players are not so motivated, so creative, or they lack the time to dedicate so much effort in the game. So, using CP to give you and the other players plot ideas is less than ideal but better than nothing situation.
Best Answer
When I have time to make a quality character with a player (rather than hashing out what will work for their first session because they just showed up ten minutes before start), I try to ask qualitative questions that players quite often forget.
On a completely radical scale you can tell everyone to take a Personality Test as though they are their character but typically Pathfinder/D&D characters don't have this level of depth. However the answer can be a nice quick reference for both you and the player when a situation comes up.