2002 Toyota Solara won’t start

Does your car have a switch for the headlights to be set to automatically come on? If so try setting it to the off position when you park it. What you have is called a parasitic drain. Something is draining power from the battery while not in use. Regular driving will keep it charged via the alternator but when it sits whatever is using power has enough time to drain the battery low. Start with the headlight switch if you have it. This can be a common cause of the drain. Also I would recommend fully charging the battery once you solve the drain issue. The battery is likely not charging back to full from the alternator between parking.