Safety
First of all, make sure your hamster is in a safe place. You probably don't want him out in the open, unless you don't have any threatening pets. If you see that your hamster is really quite small, you want to make sure that the cage is in such a place so that if he happens to escape it would be okay. Second, do not put any other types of foods or drinks, for if you do, you are taking a risk. Do not hold your hamster too often, especially when he is just arriving. Let them get used to their environment first. Stress causes death! Anyway, hamsters can bite! So be especially careful with him. Lastly, if you see strange actions in your hamster and think he may have a disease, see your local pet store expert right away.