1. Pick up the train schedule at the office of the stations you frequent. (To ask for one, just say: 시간표 주세요 or shee-gan-pyo joo-seh-yo.) The attendant will give you a little card with the train schedule. Sometimes, it's just a computer generated table for the schedule of that particular station. Sometimes, they'll give you a folding schedule of all the stations in your area.
In Cheonan, the schedule on the left is for north (or Seoul) bound trains. The schedule on the right is for south (or Asan) bound trains. The # on the far left is the hour of day. Next are the minutes of each hour the trains come on weekdays. The next number is the schedule for weekends and holidays. Sometimes there are additional notes in parentheses after the number. These usually indicate that particular train stops at an unusual station.
2. A lesson learned the hard way: The schedule changes slightly every month or two. Make sure to pick up the new schedule every so often.
3. When you're traveling to a new place - say PyoungTaek - make sure you check the departure schedule when you arrive. Then, you'll know what time you need to get back to the station without waiting around forever for the next train.
4. When traveling south-bound from north of Cheonan, make sure to look for trains with (신) or (신창) marked after the time. Or, sometimes these may be marked in red. About half of the southbound trains stop in Cheonan - rather than going all the way out to the end of the line which is ShinChang. If you want to get to the Ssang-Yong-KNU Station, you have to take the ShinChang train. If your train stops at Cheonan station, and EVERYBODY gets off. Your train is stopping in Cheonan. Just get off and wait for the next train bound for ShinChang.