Some paintings I know what the title is going in, because I am trying to depict something in particular. Other works the title comes as I go along or even when I am done. As someone mentioned re their bluejay painting, I try to give my works titles that intrigue or evoke a mood. I also try to keep in mind what the title will make someone think of if it is online and they are searching and have not seen the work yet. If it's a painting of a particular place, I will sometimes include that info in the description rather than the title. So I have a winter painting of a field in the Adirondacks but I called it "Snowy Field" and put the Adirondacks info in the description.
That said, I have seen some artists using really odd titles for their paintings that don't seem related to the work, like Talia Telfair: