How to resist the Devil?

THEREFORE submit to God. Resist the devil and he will flee from you. - James 4:7 NKJV

This verse has nothing to do with deliverance from demonic opression or possession. Noticed that the verse starts with THEREFORE? Which means it is a conclusive statement of what was discussed before hand. So what aspect of the Devil which James says we ought to resist? Lets take a look at Chap 3 onwards.

3:1-12 talks about taming the tongue. It ends off with a rhetorical question on whether one is bearing fruits with his tongue.

Does a spring send forth fresh water and bitter from the same opening? Can a fig tree, my brethren, bear olives, or a grapevine bear figs? Thus no spring yields both salt water and fresh.
James 3:11‭-‬12 NKJV

He then explains that he who shows forth good fruits by good conduct are done in the meekness of wisdom.

Who is wise and understanding among you? Let him show by good conduct that his works are done in the meekness of wisdom.
James 3:13 NKJV

But if one is bitter and self seeking, his "wisdom" is not not from heaven, but DEMONIC

But if you have bitter envy and self-seeking in your hearts, do not boast and lie against the truth. This wisdom does not descend from above, but is earthly, sensual, DEMONIC.
James 3:14‭-‬15 NKJV

So James is starting to define what he meant by demonic influence, it is the source of strife among brethrens, 4:1.

Where do wars and fights come from among you? Do they not come from your desires for pleasure that war in your members?
James 4:1 NKJV

Believers allow this demonic influence that causes bitterness because they lust for worldly desires.

You ask and do not receive, because you ask amiss, that you may spend it on your pleasures. Adulterers and adulteresses! Do you not know that friendship with the world is enmity with God? Whoever therefore wants to be a friend of the world makes himself an enemy of God.
James 4:3‭-‬4 NKJV

Thats why this section of scripture is not about deliverence from demonic possession, but about disallowing the Devil to get a foothold on us through the Sin like bitterness, envy and lusting for worldly things. It's actually about repentance.

Draw near to God and He will draw near to you. Cleanse your hands, you sinners; and purify your hearts, you double-minded. Lament and mourn and weep! Let your laughter be turned to mourning and your joy to gloom. Humble yourselves in the sight of the Lord, and He will lift you up.
James 4:8‭-‬10 NKJV