This verse in Romans is often misquoted and misused. Not every one qualifies to have all things work together for them. The first thing we see is that loving God is primary. Not the way we love our family or love our friends or even the way we love our spouse. An all encompassing, whole-hearted love that causes us to want to please God, to seek out that which makes Him happy; a love that blesses God.
The second required is that we are to be called according to His purpose. What is His purpose? That all peoples every where be saved: John 3:16 "For God so loved the world, that He gave His only begotten Son, that whosoever believeth on Him should not perish, but have everlasting life."
That we be sanctified, set apart from how the world around us behaves, but set apart for His will and His use: 1 Timothy 6:11 "But thou, O man of God, flee these things; and follow after righteousness, godliness, faith, love, patience, meekness."
But we try many times and fail to live a godly life in an ungodly world. Through the sneakiness of the devil we give into temptation and backslide into sin(s). We let him get a foothold in the door of our thoughts. We allow unrighteous thinking to settle into our hearts, thereby committing unrighteous activities. The farther we backslide, the more we think we are still alright. But we are not.
We need the holiness of God actively moving within our minds and our hearts:we need God's Holy Spirit, and we need Him poured out onto us and in us. It is The Holy Spirit of God that draws us to Him, that calls us to a life of obedience and personal discipline. It is The Holy Spirit of God that sanctifies us and makes us holy.
1 Timothy 6:12 "Fight the good fight of faith, lay hold on eternal life, whereunto thou art also called, and hast professed a good profession before many witnesses." In other words, step up, put on our spiritual armor as outlined in Ephesians 6:10-20; put on Christ as stated in Romans 13:14; but do all in love, 1 Corinthians 13.
God says to each one of us, " Sanctify yourselves therefore, and be ye holy: for I am the LORD your God." Leviticus 20:7; 1 Peter 1:16. Romans 12:2 "And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God."
Make a deliberate stand for Christ in our lives. Take careful thought and make decisions that will strengthen our resolve to live lives that are pleasing unto God. Do not just be Christ-like on the outside, but let Christ live in our hearts, our minds, our spirits. Ask for The Holy Spirit to come upon us, to fill us to overflowing that we might glorify God by our actions, our thoughts and our love: His love.