If you don't have any flight sim experience so any layout and setup might work but you need to find the right setup that is easy for you to make a muscle memory for it. I would suggest to use standard Airplane flight model because it is an engineered control setup, so everyone can memorize it fast and easy and have the best control over the plane manual flights. So its really up to you to find out what is the best for you but to start from scratch, you can use commonly suggested and used layouts then tweak it for yourself in time. There is no the best setup, there is just best one for you.
If you have an Airplane flight sim experience and you have made a muscle memory already, even tho if it has been passed for years, (let say its just like riding a bicycle so you already have that memory) then the easiest way to adapt to a space sim is to use the already existed muscle memory and just add new ones on that with some small tweaks. Here I share my overall setup which is based on my Airplane flight sim habits. I hope this would be some use for you.
Left Hand :
All axis are for strafing, X for left and right, Y for up and down.
I don't use twist on left hand for any movement. (this is just a personal preference )
Here I didn't add thrust to Y because I needed to create a new complex thrust forward/back and left and right strafe muscle memory, which I couldn't manage to overcome and I decided its best for me to not use Thrust on left hand, however my old habit for left hand was thrust but with a few practice I managed to replace it to up and down strafe. In order to make it easier for me to memorize up/down strafe, I revered it so just like pitching, pulling back is moving up and pulling down is moving down. I managed to get used to this new movement easily.
All buttons on left hand are related to flight controls only, like speed limiter boost, couple toggle etc.
The only thing that is not related to movement on my left hand is shield control on hat. I found out that having those on left hand makes my dog fight shield control very easier. (This is my personal preference.)
Right Hand :
Ok, I did set this up exactly the same way as an usual airplane control setup.
X is roll. yes this is roll, just because of my airplane control habit so I didn't want to change it, I don't use yaw much in Star Citizen maybe I should but I never had the feeling that something is missing because of this so Its up to you make X roll or yaw.
Y is pitch and twist for me in this case is yaw which I heavily curved it and made it a very slow motion for yaw. (Just a personal preference from air plane flight muscle memory)
All buttons are for targeting and weapon control
Thrust :
Ok this part is a bit unusual but might be interesting. I use a pedal for Thrust forward and backwards, natural muscle memory from daily car driving habit ;)
Alright, Pedals in airplane sims are mostly used for left and right yaw and tail flaps control, so this part might need a bit work. If you have a 4 ways pedal then you can use pedals for strafe and left hand stick for thrust but in this case using a thrust controller on left is more useful than a left hand stick.
And last but not the least, I use head track for free look all the time instead of using right hat for free look. I'm using in game face track and it does work pretty good.
I hope this would be useful, and I would be happy if anyone would add some advises on my setup or criticize this setup so I might learn new things.