How do deeply spiritual muslims maintain their devotion to Allah and do the necessities to be successful?

You do not have to be deeply spiritual. The connection with Allah only comes from submitting to Allah, Beginning of the day end of the day and some watches of the night. This refers to the salat described in the QUran not the ritual exercises of up and down people do and call it prayer. It is easy and it will amaze you as to how rewarding the connection with Allah is. I mean in this wordily as well.