How you add a lighter (power socket) will depend in part on whether this is a positive ground or negative ground car since most over-the-counter sockets are designed to ground to the body and many applications (such as chargers and other electronics) are expecting a particular polarity.
As for location -- again that will depend on which model you have and whether you want it in plain sight or in a stealth locale.
In any case, you will want the power side fused.
I used an extra fuse box (from a TR4) and mounted the socket in a non-conductive panel (cars are + ground) in a location under the drivers side dash (wanted it stealth).