How do I get my ball python to eat?

It's not uncommon for a new snake (especially a baby) to not eat for the first week or two. It is important you have thermometers that accurately read the heat of the cage. Incorrect heating will make them unable to digest and so they will not eat (or will regurgitate). Also, humidity should be around 60%. Ball pythons are not forgiving of husbandry errors and will not eat if anything is wrong. Make sure it has a waterbowl it can soak in and at least two hides.

Also, you made it sound like you've tried to feed it multiple times already. That's not a good idea. Offer food once a week. Offering food too often can cause stress and make them less likely to eat. The most I would offer it would be every 5 days. Something you can try is putting the snake and dead, warm mouse in a brown paper lunchbag, standing the bag upright in the cage. Leave the room for an hour. This method works for snakes that are shy eaters and don't want to be watched when feeding. You have to remember that they are at their most vulnerable when feeding, unable to defend themselves. Now the bag trick can sometimes take two or three tries before it works because the snake does have to get used to it and figure out what the bag is and that it is safe. What I like about this is that (assuming you get an appropriately sized bag for the size the snake is) the snake should have little trouble tipping the bag over when it wants to get out. Then it's already in its cage and can go hide. There are other feeding methods, but you're not at the point where you need to worry about live feeding yet.

One more thing: handling it will only add to its stress. I always tell people to never start handling their new pet until it has taken at least 1 meal (and you should not handle a snake for the first 24-48 hrs after it eats as well). You want this animal to have time to adjust to its new environment. Handling it will only cause it to stress and make it less likely to eat. The only reason your hand should be going in the cage is to change the water daily.

Feel free to pm me via YA if you need more assistance with this. I've had several types of snakes, including some picky ball pythons.

Generally, if you are having a hard time getting a python to eat, try tickling him (or her) behind her (or him) left knee.