If you are riding in a cochette, realize that you will be lying down the whole time. They don't give you enough room to sit up very well, and are fairly cramped. If you are taking a night train that leaves after 7pm, you are to mark the following day on your pass. Some things besides trains are included in your Eurail Pass, but check to make sure they don't want you to mark a day. If they do require you to mark a day, try to arrange it so that you go on the day you arrive so that the day is already marked.
Information boothes at train stations can be very helpful, but always have long lines.
If you can figure out the train schedules on your own, you'll be much more happy. If you know where you want to go on what day, don't go to the information booth just to find out the departure time. Instead, just get in the ticket line and tell the salesperson where you want to go on what day and they will figure it out from there. Sometimes you can go to your destination city on a train that doesn't go directly there, but stops there on its way somewhere else. Often times, these trains take less time than ones that have your city of choice as their final destination because they make fewer stops in between.