To increase a magnet's strength, you should:
Choose a neodymium magnet with a high BHmax value for greater magnetic power (note that N52 is not always stronger than N38 - height matters!),
Avoid high temperatures which weaken magnetic properties, especially above the Curie temperature,
Apply an external magnetic field, for instance, by using another, stronger magnet or an electromagnet,
Creating multi-pole arrangements by combining magnets can concentrate magnetic forces in one direction, enhancing their overall power. Additionally, using a magnetic lens made of low-carbon metal, with a thickness comparable to the magnet, can further strengthen the magnet's magnetic force by up to 100%.
It's important to follow the manufacturer's recommendations and consult an expert for specialized applications.