1. Keep Your Heart
Proverbs 4:23 - The word "keep" means "to walk guard" around. Don't let any type of sin conquer your heart. Keep them out. Some examples are found in Mark 7:21-23.
2. Watch For Your Soul
Hebrews 13:17 - The soul of a righteous man can be vexed (worn down) by worldliness. II Peter 2:8. We need to watch out for the world, or it will get to us and wear it down. Other scriptures to study: I Peter 2:11, I Thessalonians 5:23.
3. Rule Your Spirit
Proverbs 25:28, 16:32 - The spirit of man is their emotions and will. Emotions like rage, temper, anger, depression, etc. can ruin you if they control you. With God's help, control your emotions, don't let them control you.
4. Captivate Your Mind
II Corinthians 10:4-6 - "Bring into captivity every thought." The human mind can only think about one thing at a time. Thus it is not impossible for God to control your mind. Yield your mind to the Holy Spirit each moment. Ask Him to take control.
5. Bring Your Body Into Subjection
I Corinthians 9:27 - The appetites of the body are called "the flesh" in the scriptures. You can control your appetites, or they can control you. Appetites include: eating, drinking, sleeping, sexuality, nervous system (often triggers urges to smoke, drink, use drugs, etc.) The Lord can help you with this if you'll surrender your all to Christ - Galatians 5:16, 24-25.
6. Tame the Tongue
James 3:8 - It is a sign of perfection if we can tame the tongue. (James 3:2) The tongue needs to be bridled. Its power for good or evil is awesome: James 3:5-6, Proverbs 18:21
7. Commune With the Holy Spirit
II Corinthians 13:14 - The Holy Spirit is a real person. He is God. He lives inside of us as believers. Talk to Him. Have fellowship with Him. Get to know Him as real as you know God the Father and God the son.
Where did Cain get his wife?
This has to be one of the most frequently asked questions of the Bible. More likely than not, Cain married one of his unnamed sisters (or perhaps even a niece). Adam and Eve likely had many children by the time of Cain's exodus to the land of Nod and whether Cain had already married or acquired his wife post-exile, it would not require any interpretive gymnastics to understand his wife as having been a close relative.
Just because no sisters are directly indicated does not mean that Adam and Eve had no daughters at the time of Abel's murder. A child of the patriarchs was not usually mentioned unless he fulfilled one of two narrative functions: he was integral to one of the stories within the Jewish mythos or he was to become the progenitor of a nation.
If either of those two functions were not fulfilled, a child's existence was rarely even indicated (especially if that child was female); therefore, it is really no great shock to find that Cain married a woman who earned no previous mention in Scripture.