This joyful song by Sandi Patty tells how to magnify the Lord: https://www.youtube.com/watch?v=yrJDNuzdioA
When we magnify, it enlarges the subject. How do we magnify God? By making Him larger in the world by spreading His word and doing His work, showing how large a part of our life He is.
When we magnify, it also shows our subject in more detail. We can magnify God by studying the details about Him in Scripture, songs, prayers and meditation. Get to know everything we can about Him so we can be in a more intimate relationship with him.