A few tips for scene composition I would suggest:

Get in the practice of Viewing the scene using different cameras while setting it up.

Set you main Camera Preview mode to be solid shaded so you can see the position of the main camera when looking through another camera (helps when trying to prevent clipping)

You can sometimes fix clipping issues with walls by adjusting various camera settings such as Focal Length and Scale.  Be careful on how much you change Focal Length as it can greatly alter the overall look. +/- 10 should not alter the look too severely though.

I almost always render to a specific resolution, and only use fit in preview window when doing simple lighting, texture, or composition tests.

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