First, remember you have no need to go far away. Look around you and your house: maybe close your city or town are located interesting areas? Look in internet, on local sites. I advise you to buy a tourist guide for your surroundings, it can help you very much. And remember, choose not more than two or three places. You haven’t so much time to see everything. But don’t worry – it is located close to you, co you can come back there anytime.
Check open hours and ticket’s price, if it is needed. If you go hiking or trekking, remember to verify a weather. Mountains during storm or heavy rain are extremely dangerous! Of course, sightseeing in the rain is not so pleasant too but definitely safer. And you can always hide from rain in shop, bar or cafe. Anyway, checking weather before you leave is very important.
Before you go for a trip, you need to make sure, if there is any possibility to come back. Once I had forgotten about that and had to sleep in railway station because the last train was leave one hour ago. I was lucky because that night was very warm but since then I always check my trains twice.
And the last important thing you must remember: If chosen area have no restaurants or bars, you must take with yourself packed lunch. And water. Always take water with you.