This is a very basic guide mostly for first time FSX users..It is a good starting point for in game settings along with your Nvidia Control Panel settings to get you up and running in pretty good shape
This again is only a fair start..You WILL depending on your equipment have to either reduce or bump some settings..

Lets start with the Nvidia Control Panel:
First make sure that your screen resolution and refresh rate are set for your monitor (native resolutions are best)
In 3D Settings:
1) Adjust image settings W/ preview---set to: Use The Advanced 3D Image Settings
2) Manage 3D Settings
a) Anisotropic 4X
b) Antialaising-setting 8X
c) Multi-Display/mixed GPU acceleration set it for single or two(whatever you have)
d) Vertical Sync Force on



Now on to FSX.....On the front opening screen select customize.....

Graphics:
Target Frame Rate----22-30 (lower Vid cards start low/better vid cards go higher)
Set (YOUR) monitors resolution
Filtering------Anisotropic
Check----- Anti-Alaising
Global Texture resolution--- high or Very High (depending on your cards quality again)
Check--- Lens Flair
Check---- Advanced animations
Aircraft: Leave at default for now... The 3D box checked will start you in virtual cockpit while the 2D box checked will start you in 2D panel(like FS9 does)
Scenery: This is where you will do the most changes depending on your CPU and Graphic Cards abilities

Level Of Detail Radius----- Large
Mesh complexity------80
Mesh resolution----19m
Texture Resolution---30
Water Effects--- Low 2X ( this is a killer on some systems/reduce as needed)
Scenery Complexity----Dense (this also is a highly adjusted setting depending on your equipment)
Autogen density------Dense (this also is a highly adjusted setting depending on your equipment
Check----Ground scenery casts Shadows
Special Effects Detail-----High
Traffic: We will start very low here as it can cripple some machines if set too high..Advance these at your discretion

Airline Traffic density-----20%
General Avaition Traffic Density----20%
Airport Vehicle Density----20%
Set (ALL) Land and Sea Traffic at -----20% too


Thats it..You have just set your Video Card and FSX settibgs..You should now be able to fly with some success...Remember these are just starters. You will more than likely need to decrease /increase some settings.