Leave pin 1 to 8 open. Add another gain stage ahead of the LM386.

^{simulate this circuit – Schematic created using CircuitLab}

This non inverting amplifier has a gain of \$A=1+\dfrac{R_f}{R_i}\$. Gain can be increased by increasing the value of the feedback resistor. Add the LM386 gain stage and total gain becomes \$A=20(1+\dfrac{R_f}{R_i})\$. However, if this is for that induction loop you keep talking about, I doubt you will ever be able to get enough power out of an LM386.

Leave pin 1 to 8 open. Add another gain stage ahead of the LM386.

^{simulate this circuit – Schematic created using CircuitLab}

This non inverting amplifier has a gain of \$A=1+\dfrac{R_f}{R_i}\$. Gain can be increased by increasing the value of the feedback resistor. Add the LM386 gain stage and total gain becomes \$A=20(1+\dfrac{R_f}{R_i})\$.

The voltage divider and capacitor add a DC bias to the the non-inverting pin. This will allow it run from a single supply, and acts as a 50 Hz high pass filter. Do not forget to add C2 as well. Without it, the amplifier will just slam the positive rail.

However, if this is for that induction loop you keep talking about, I doubt you will ever be able to get enough power out of an LM386.