What else could i do to an electromagnet to change its strength?

To change the strength of an electromagnet, you can increase the current flowing through the coil, as a higher current generates a stronger magnetic field. Additionally, you can increase the number of turns in the coil, which also enhances the magnetic field strength. Using a core material with higher magnetic permeability, such as iron, can further amplify the magnetic field created by the electromagnet. Lastly, reducing the air gap between the electromagnet and the object it attracts can improve its effective strength.