Hi everyone,
First post here. Reading this thread convinced me to register. I like the helpfull advice and desire to teach I'm seeing here. I need some learnin' myself.
Back on topic,
Although all the advice being given is correct it may be that it is something much more simple.
When I first started with FSX (a whole 8 months ago) I had trouble trimming several of the aircraft correctly. I felt I was flying a yo-yo. What helped me was;
1/ taking the lessons provided (still had some troubles),
2/ adjusted the repeat rate in the control settings for the trim buttons and 3/ eventually purchased a Saitek x-52 and mapped the trim to a rotary knob (this worked best).
Although you need propper technique it won't help you much if your controls are too coarse to dial it in. This can be very frustrating and make it much harder to learn that proper technique.
I may be way off here but thought I might point this out.
Repeat rate for trim buttons is accessed through Settings - Controls - Buttons/Keys in FSX.
Look under Settings - Controls - Control Axes to map your trim to a rotary knob or slider if you have one availible. I found this worked best for fine tuning.
If I am wrong here maybe this can help someone else searching for an answer to the same issue.
Rob