Like with any electronic, I would just recommend keeping your system clean. Sega CD systems are old though, so just try and treat it gently.
The model 2 Sega CDs are built a lot better than the model 1 Sega CDs, so I really don't think you'll have too many problems with it though. I own both a model 1 and a model 2. Out of the two models, the model 1 broke a week after I got it a couple of years ago. My model 2 I've had for about 4 or 5 months now, and I've had no problems with it at all and it plays all my Sega CD games beautifully.
I know some people play their Sega CD games on emulators, and that's what I used to do before I got my Sega CD. The benefit of playing the games on an emulator is that if you rip your own games and play them, you won't have to worry about loading times and so the games run faster. However, I love playing games on their original hardware. There is nothing better than grabbing a controller, and sitting in front of the TV playing a game, lol.
Also, if you don't already have Lunar Eternal Blue, get it too. I would also recommend getting other Working Design games for the system such as Popful Mail and Vay.