Far as I know, there isn't really any special precautions you need to take in the placement of your dry box. Some of the precautions I would think would be:
1. Avoid direct sunlight;
2. Avoid humid environment;
3. Avoid dusty environment.
I guess these are quite "standard" precautions you would have taken already. Placing a dry box beside a computer might not be a good idea as the computer can be hot and attracts dust.
Kelvin