Shoot Whole Roll. You may never have another chance. Bracket Exposures Widely. Do Not Use Flash. If your camera automatically engages the flash at low light levels, disengage the flash or cover the flash.
Poor focus is a common defect of eclipse photography.
The infinity setting on cameras will not necessarily give best focus especially with long focus lenses. If you have a safe photographic solar filter, confirm your focus on the edge of the partially occulted Sun. Turn Autofocus Off. If using autofocus to focus your camera, turn the autofocus off once camera is focused. Tape Camera Settings.