"One who fears G-d recognizes His involvement in our everyday lives. "I have set G-d before me always" (Psalms 16:8) – before me at my own level. Unlike those who mistakenly think of G-d as being far above and removed from earthly matters, David perceives G-d’s presence on the level of his own earthly existence. I have set G-d before me, he says, in everything I do. Nothing here on earth is so small or insignificant that G-d would be indifferent to it. Whatever I am, whatever I wish to accomplish, lies clearly before His eyes." (Hirsch Torah Commentary, Psalm 16.8)

A person can choose to submit to G-d’s Will out of fear of the punishment to which he will be subjected if he violates G-d’s Will [or, on the other end of the spectrum, out of desire for the reward that G-d has promised those who do His Will]. The Sages (Talmud, Tractate Sotah) refer to this motivation (as well as other "self-serving" motivations) for doing G-d’s Will as "serving G-d with ulterior motives [whether to avoid punishment, to earn reward or to gain some benefit]."
Although this is not the ideal motivation for serving G-d, the Sages (ibid.) stress that it is valid in its own right, and further, that it is important as a "starting point," a basis upon which one can build a stronger relationship with G-d. "A person should always accustom himself to study Torah and perform G-d’s mitzvot even if only for ulterior motives, since service even for ulterior motives will lead eventually to service with pure motives."
The purest and most effective motivation for submitting to G-d’s Will is to visualize – with no consideration of reward or punishment – some "image" of G-d’s exalted nature and His perfection.
Consider a person’s behavior when he is in the presence of a greatly revered official, especially one who possesses a sterling character and superior wisdom. Even if the person does not fear that any harm will result from his violating the protocols that befit this highly respected official, nevertheless, he will undoubtedly be in awe of the official, and will not dare to transgress the official’s rules.
Similarly, when a person recognizes G-d’s exalted presence, which is infinitely greater than that of any human being, he is inspired to submit to G-d’s Will. The recognition of G-d’s omnipotence – He knows everything about us, whether hidden or revealed – and of G-d’s perfect wisdom – as opposed to man’s necessarily limited knowledge and understanding, will lead him to do G-d’s Will readily, out of his great awe for G-d.