Here are the settings we used for the TCL S305 review, and some recommendations to obtain the best settings for your use.
We used the 'Movie' picture mode to get as close as possible to our calibration goal which gives a warm picture look. Note that this TV does not feature a calibration menu, so the only changes possible are from the 'Option' and 'Advanced picture settings' menu. The 'TV brightness' was set to 'Brighter' since it allowed the use of brighter values accessible under the 'Advanced picture settings' menu. We used 'Direct' 'Picture size, as we did not want the TV to change the screen ratio of the video input. You may use this setting to adapt the size of the video content you are watching to fill your TV screen.
To reach our desired luminance of 100 cd/m² in our totally dark room, we used 'Backlight' value of 12. You should increase this value to match to your room lighting and this won't affect picture quality. 'Brightness' was left at 50 and 'Contrast' at 80, their default value. 'Sharpness' was set to 0, since we did not want to have any overshapness and aim to leave the content as true to the source as possible. 'Color' was left to 50 and 'Tint' to 0, their default values. 'Color temperature' was set to 'Warm', but it can be changed to a colder setting if you find the overall picture too yellowish.
Note that the 'Game mode' setting did not change anything in our input lag measurement, so you can play video games without setting 'Game mode' on and you have the same input lag.