I have trouble remembering to take my oral medication every day. What's a good way to remember? What should I do if I forget a dose?

Cell phone alert. Almost everyone has a fancy enough cell phone with various alert sounds that is possible to select a specific daily one as a medication reminder. This really does help as long as you keep the medication in a small, individual pill box with you.
Containers. The pharmacy has special containers divided up by day so that you can see what you have taken and what you still need to take.
Pair it. Pair the medication with an activity you already do every day, like brushing your teeth. Put the bottle by your toothbrush. If you miss a dose, do not double up the next day. Just continue to take it as prescribed and if you miss a dose, you miss it.