Be careful if you’re sitting next to someone whose dominant hand is different from your own. Be conscientious of your movements to avoid accidentally knocking elbows with them.
This is a more flexible position than if you held the spoon in, say, a fist, or between your thumb and index finger.
Eating food slowly will also help you best enjoy the taste and texture of your food.
In general, you should not place your spoon back in a bowl when you finish eating. This could confuse waitstaff, as they may think you’re still eating. However, if no plate was provided, it’s okay to put your spoon back in the bowl. You do not want to get food residue on the table.