What would be the best way to organise and categorise static IP addresses for the business

I'm a new network administrator at a company, with very little experience (still studying).

I often run into the problem where the IP addresses become messy and confusing and disorganised very quickly.

What do you think the best way to organise these IP addresses would be?

Basically, my boss wants me to categorise the IP addresses by device type (desktops from .20 - .50, mobile devices from .51 - .100, for example) but this hasn't worked well and we both haven't been keeping great track of it.

Is there any other alternative to this?