Headlight/brakelight problem

Check the grounds by the lights.

Sorry, I'm very inexperienced with this stuff. Could you tell me where to look as if I were a two year old? And what exactly am I looking for?

Thanks:)

First off let me that it's probably not one thing causing both problems.

Up at the front corners of the car are some small plates (about 2" x 2") that are bolted to the inner fenders. These plates have terminals sticking out of them at an angle that ground connections for various components are pushed onto. All this is open to corrosion, (no waterproof connectors etc.) and the resulting poor connections. Also the terminals that connect the wires to the bulbs are a little small for the job they're doing, so look to see if there's any heat damage in any of the plastic around the connectors.

In the rear, it's a little simpler, the bulbs in each taillight section share a ground wire. Find that wire and make sure that it's connections (both ends) are clean and tight. In addition, clean the bulb and contacts.

Also there's a round red relay mounted with the fuses that determines when there's a failed bulb in those circuits. Sometimes it gets bad solder connections inside it, causing intermittent problems. However, the headlight and brakelight circuits are totally separate inside it, so it's unlikely to be causing both problems.