I'm not a senior, but just my $0.02. To master manual mode, shoot in other modes (Auto, P, A, S) first and try to understand why the camera choose such settings for such environment/setting. So far, I've only used Manual mode when the environment is tricky where it "tricks" your camera to overexpose or underexpose certain scenes.
If you are new, I suggest that you shoot in semi auto modes (as listed above). That way, you will have more time to focus on composition and stuffs rather than camera settings. If you see some numbers blinking when looking thru the viewfinder, it means that your current settings is either severely overexposed or underexposed. In this kind of situation, try to play around by changing values you can control, ISO, Aperture and Shutter Speed.
Tripod - Best to get if you are landscaping at night or shooting long exposures.
Lastly, I hope you at least have a drybox (with silica gel loaded)....