Determining resistor values for common source amplifier
I consider Rs is connected to GND.

The gain will be equal to:

-gm*(Rd//R5//Rload)

note: double slash means 'in parallel'.

Where gm = 2*Id/(Vgs-Vtn(***))

(***) - Mosfet parameter, known as threshold voltage.

And Id = 1/2 * Kn(mosfet parameter) * (Vgs-Vtn)^2 

For AC small signal, source of the nMos will be at ground level, but for DC, you have to consider the voltage difference between gate and source, and the voltage on the drain should satisfy:

Vds &gt; Vgs - Vtn

Combine all these requirements and formulas and try to arrange DC values Vg, Vd, Vs and Id so that you achieve your desired gain.