how to enhance the magnetism of the magnet

how to enhance the magnetism of the magnet
I summarize a bit, there are seven kinds of ways, a round magnet if it is, then the middle of an iron core, can enhance the magnetic circular magnet.
2 the magnetic field lines can be concentrated by way of the magnet piece of magnetic iron absorption in cup magnet  the magnetic iron plate and on the side edges of the magnetic field will result in higher
3 plus porcelain with increased magnetic!
4 improved magnetic content.
5 plus increase in the magnetic coil is energized.
6 lines by increasing and increasing the electromagnet coil turns, coil winding, the number of laps the better!