Here is an important truth that you must always keep in mind: All quotations from the Old Testament must be checked to see if there is some New Testament truth that overrides it. For example, slaying lambs has been overridden by the Lamb of God already slain for us. In the same way, we must remember that Daniel prayed at a time when Satan and his hosts had not yet been defeated on Calvary. That is why there was a conflict then with Satan (in the heavenlies) for three weeks (Dan.10:12,13). But we are now living on this side of the cross, where Satan has been defeated. So, we don't have to struggle with him for three weeks now. We stand on Christ's victory. This is a truth that very few are teaching.
We read clearly in Col.2:14, 15 and Heb.2:14 that Satan was defeated (not destroyed but disarmed) on the cross. So today, we first submit (give ourselves) to God totally and then stand on the victory of Christ and resist Satan in Jesus' name. And Satan will flee from us at once (James 4:7). He will flee from us at the speed of lightning, which is 186,000 miles (or 300,000 kilometres) per second - because Jesus said that He saw "Satan falling from heaven like lightning" (Luke 10:18). (This, by the way, is a good question to ask in a Bible quiz on James 4:7: "At what speed does Satan flee from us when we resist him?")
But if your lives are not cleansed in Christ's blood constantly by regular confession of sin (as and when you are pricked in your conscience), then you won't have power over Satan. So, keep your conscience clean by confessing your sins to the Lord.
God is a loving Father. You must always find your security in Him. The best earthly father is but a faint replica of God. So, you can imagine how much God loves you. You must be secure in His love always and love Him in return deeply. You must never do anything that displeases Him. And when you fall (as will happen now and then), repent immediately and come back to Him in sorrow, and keep your heart clean through Jesus' blood at all times.
Many charismatic preachers major in their preaching on faith for material things and healing and on casting out demons, and then pressure people to give them their money. Some other preachers major on psychological methods of comforting Christians, rather than getting them to have faith in God's promises. So be careful to avoid the false teachings about "inner healing", "the power of positive thinking", and "generational curses", etc., which are widely prevalent these days. It is best to stick to the language of the New Testament in spiritual matters. Study God's Word and then you won't be deceived.
One of Satan's chief weapons is "fear". He uses it constantly. When believers try to frighten others or threaten others, they are (albeit unconsciously) in fellowship with Satan, because they are using a weapon from Satan's armoury. "God does not give us the spirit of fear" (2Tim.1:7). Fear is always a weapon of Satan. So, we should not be afraid of the threats and intimidatory tactics that men use against us. Such men are all agents of Satan, even if they call themselves "believers". This is a lesson for us to learn for our whole life.