Did you make sure it is charged?
Also make sure the charger cord is actually working. You may want to try it on a different device, or try a different cord on yours.
If these don't work, you may be in need of a new battery. If the tablet is still under warranty, then you would need to contact the manufacturer about it. If it isn't under warranty, you are free to either find someone to do the work for you, or do it yourself. Most batteries on tablets aren't easy to remove, one must be very careful, but it can be done.