First of all, you need to look at the neck. Probably, not everyone will go to the store with a ruler, but you can just take a guitar and see the edge of the neck on both sides, it should be a straight line, without convolutions and waves. The quality of the sound depends on the quality of the neck; a good neck makes all the notes sound fully, without ringing and other extraneous sounds.

You need to pay attention to the quality of the gluing. Look through the joints of the neck and shell, there should not be any cracks. There should also be no gaps or cracks between the stand and the deck, otherwise, you risk getting a torn stand.

If you did not find any visible defects, it means that the instrument is quite suitable for playing and, most likely, the guitar is good.

The article at https://musiety.com/best-acoustic-electric-guitar-under-500/ offers some useful tips on how to select an acoustic guitar.

It easier to choose a guitar in stores with a workshop. In a workshop, the specialists additionally tune guitars to make them easier to play. Often the instrument with factory tuning has a large distance between the neck and the strings, which complicates the performance, especially for beginner guitarists. Also, stops often overhang that literally can cut hands. Specialists lower the strings and grind frets, if necessary, absolutely for free.