From your examples, it seems as if you are praying and asking for natural blessings – not spiritual blessings. Jesus taught us not to be concerned about these natural things because God, our Father, knows you need these things. Instead the focus of your prayers and your life should be the kingdom of God.
Matthew 6:25-26, 30-33 (NKJV), 25 “Therefore I say to you, do not worry about your life, what you will eat or what you will drink; nor about your body, what you will put on. Is not life more than food and the body more than clothing? 26 Look at the birds of the air, for they neither sow nor reap nor gather into barns; yet your heavenly Father feeds them. Are you not of more value than they?” … 30… “O you of little faith? 31 Therefore do not worry, saying, ‘What shall we eat?’ or ‘What shall we drink?’ or ‘What shall we wear?’ 32 For after all these things the Gentiles seek. For your heavenly Father knows that you need all these things. 33 But seek first the kingdom of God and His righteousness, and all these things shall be added to you.”
Perhaps instead of praying for success in business, you might pray that God would guide you to make business decisions which would glorify Him. Or, if a business is not doing well, you could ask God to show you where He wants you to work. In a different job, you may have more time to worship and to serve God than at your present business.
Your other example was about health. Many times our health problems draw us closer to God. We may pray more, read the Bible more, see God’s love more clearly than we did when we had good health. Paul asked God to heal a health problem but, God responded, “‘My grace is sufficient for you, for my power is made perfect in weakness.’ Therefore I (Paul) will boast all the more gladly about my weaknesses, so that Christ's power may rest on me.” 2 Corinthians 12:9 (NIV).
So, your seemingly unanswered prayers may indeed be answered prayers, but answered in a way you did not understand. God may be saying not this way but a different way. In these situations, it is not a matter of faith, but of following God’s direction. Repeated prayers are fine, but God may be answering: “yes, no, wait, or My way is a different way.”
Isaiah 55:8-9 (NKJV), 8 "For My thoughts are not your thoughts, Nor are your ways My ways," says the LORD. 9 "For as the heavens are higher than the earth, So are My ways higher than your ways…”
Download the free PDF: "How God Answers Prayer"