I have finally been using my Nikon D300S regularly after buying it several years ago. My problem is with metering, particularly for landscapes during the day. I am traveling and take photos out the passenger window of the car or while on the move hiking or whatever. I rarely have minutes to set up a shot. I shoot in manual and mostly use the single focus window so I can choose what is in focus. Most of the time using the camera meter, my photos are 1-4 stops over exposed. I try to check the exposure using the photo playback on the camera, but it is difficult to see in the sunshine. If I have time take several exposures of the same shot.
Any suggestions?
Thank you

I'm going to try to slow us down a little bit here. First...you don't mention being unhappy with focus results, so I'm going to put that on the back burner for now. Second...you mention that you are shooting out the window of the car. I'm going to guess that means you are shooting while the car is underway. We'll come back and address challenges related to that in a minute. Third...you imply that that ALL of your images are overexposed. So let's start there. I can't deduce how experienced you are, so I'm going to try to say what follows pretty plainly. If it doesn't match your experience, I apologize in advance and will adjust our future communication accordingly.

The first step is to determine whether your camera is overexposing everything, or just those taken from the car. Go out in the back yard and experiment. Are those photographs overexposed? Take some that do not include any sky. Are they overexposed?

I would actually expect, when shooting from a car window, that any wrong exposures would be underexposed...as a result of accidentally metering on the sky, causing the landscape to be recorded too dark. This suggests to me that something may be dialed into Exposure Compensation that is causing the camera to give you a meter indication that leads you to overexposing your images. Fortunately, this is easy to check. Simply press the Exposure Compensation button (the one marked "+/-" immediately next to the shutter button). If you see any number other than "0" shown in the top display window, then you have exposure compensation dialed in. It can be easily removed by turning the main command dial (the one on the back of the camera).

Ordinarily I agree with more than 98% of what Gene says. But I disagree in this case. There is really no time when shooting from a moving car to deal with spot metering and making mental adjustments, even though that is quite a good way to meter under normal circumstances. Instead, I would use center-weighted metering to set exposure. It's the top of the three choices on the metering switch next to the viewfinder. As you learn, you can use the AE-L/AF-L button inside that selector switch ring to meter on one part of a scene, then recompose. Or with Exposure Compensation (+2 stops) and Spot Metering (the bottom choice) to quickly and easily do what Gene has suggested.

The last big questions you need to deal with are sensitivity (ISO) and shooting mode. If your car is moving, or even if you are stopped shooting through the window at what is almost always an awkward angle, you are going to need to use as fast a shutter speed as possible to control the movement of the camera (or the car). The D300 & D300s were quite a bit better than the cameras that came before them at using higher ISOs, but are a bit limited compared to today's cameras. Even so, you should be able to get pretty nice results at ISOs of 640 or even 800, and you might even be able to go a little bit higher. This will allow you to use higher shutter speeds to reduce the effects of motion. I would not use auto ISO with this camera. The range over which it can act is too limited to be of much real use.

So once you have the higher ISO dialed in, you need to establish your exposure. You don't tell us what lenses you have, so you are going to have to take this next material as guidance...you will have to adjust it based on the capability of your lens. The higher the shutter speed you can use (and where the lens has aperture available to respond), the better the results you are likely to get. With your camera your target is probably going to be somewhere around 1/400 or 1/800, depending on your lens. If it were me, I'd start with Program mode and look to see what kinds of exposures the camera is available to put together. Then I might switch to Shutter priority mode and see how fast I can go and still provide proper exposure (or I might just stay in Program mode).

Above all, don't get frustrated. What you are trying to do is difficult. Work to solve the basic problem first, then go on from there.

I have finally been using my Nikon D300S regularly after buying it several years ago. My problem is with metering, particularly for landscapes during the day. I am traveling and take photos out the passenger window of the car or while on the move hiking or whatever. I rarely have minutes to set up a shot. I shoot in manual and mostly use the single focus window so I can choose what is in focus. Most of the time using the camera meter, my photos are 1-4 stops over exposed. I try to check the exposure using the photo playback on the camera, but it is difficult to see in the sunshine. If I have time take several exposures of the same shot.
Any suggestions?
Thank you

Thank you all, I am learning something from each comment and really appreciate it.
My lens is the AF-S NIKKOR 18-200mm 1:3.5-5.6GII ED. It came with the camera. I would like to get another lens, possibly up to a 300mm, but like the simplicity of just one lens right now. (I did have a second lens, but it ended up in the laundry on one of our first stops last year)
About my background - I am an engineer, not an artist, but have had a passion for photography since I was 8, picking it up when time allowed, very inconsistently. My husband and I decided to take a "gap year" last February. We are in our late 50's, quit great jobs, rented our house, bought a small pop-up and then covid hit. I had planned to replace this camera with something lighter but all the shops were closed. Despite my frustrations, I am glad I didn't replace it. I use my phone while trail running, long hikes or cycling. The photos are mainly for documenting our trip. My husband does the writing and I add the pictures at www.travelswithtoohey.com. We have been in some beautiful places and I'd like to be able to capture that.
Our next stop is the Grand Canyon, I know all your advice will be helpful. Hopefully I will have some success and I'll let you know when we get back online.