In the sacrament prayers that we hear in church every Sunday, we are promised that we can have the spirit to always be with us if we do certain things: take upon ourselves the name of Christ, always remember Christ, and keep Christ's commandments (Doctrine & Covenants 20:77). So if we do these three things, we are promised by God that the Holy Ghost will always be with us. I really like the word always.
However, it is so easy to say these things but it is much harder to live them. It sounds clique but there is opposition in all things. Especially in maintaining the Spirit. There are always other voices calling to us and getting in the way of things that will help us to maintain our relationship with the Holy Ghost.
Maintaining the spirit is like exercising. If an Olympic athlete stops exercising and practicing, they will loose the physic they have worked so hard to gain. In addition, I don't think their teammates would be supportive of their choice and wouldn't hang out with them anymore. They would have different priorities. This applies to your spiritual physic as well. If you stop exercising spiritually, how is the Holy Ghost (your "teammate" since baptism) suppose to be with you? It is easy to loose that connection when we are not doing the things that invite the Spirit to be with us. We are here on earth to learn so many things. One of those things is to let our spirit control our natural man. In other words, how to live to constantly have the spirit with us.
The best way to let your spirit take control is with some help from the Holy Ghost. The influence of the Holy Ghost will help you to want to do good and turn your back on the bad. This happened to the people of King Benjamin in the Book of Mormon after the Holy Ghost helped them to change their hearts (Mosiah 5:2). You have to take the steps to have the Holy Ghost with you, but it will become easier because He will help you to continue walking down this path. The best way to keep the Holy Ghost with you and maintain your spirituality is to simply keep the covenant we made at baptism and renew every Sunday.
1. Take upon ourselves the name of Christ
You have already been baptized a member of the Church of Jesus Christ of Latter-Day Saints and by doing so took Christ's name upon yourself. You also take upon yourself Christ's name by striving to think and act like Christ (Mosiah 18:9). Be proud to have eaten of the fruit of life and stay by the tree of life (1 Nephi 8)!
This lesson has lot of insights on taking his name upon us. "What does it mean to take upon myself the name of Christ?"
2. Always remember Christ
Something that I like to so help myself always remember Christ is to pray often and thank God for my blessings and for the atonement of Jesus Christ for me. I will pray in my heart as I walk to and from school and it helps me to feel God's love through the Holy Ghost. There are many other things that we can do to always remember Christ like: having paintings depicting Christ in our homes, taking the sacrament, reading our scriptures, and pondering how we are using his atonement daily.
Two talks to read on this topic are: "They That Do Always Remember Him" by Elder Claudio R. M. Costa and "To Always Remember Him" by Elder D. Todd Christofferson
3. Keep Christ's commandments
This one is a little more obvious on what to do; just keep the commandments. The only thing I have to add is to remember the higher law that Christ taught the people on the sermon on the mount (Matt 5-8). The letter of the law is one thing but we are expected to grow to live the spirit of the law as well.
In Preach My Gospel, it says that the Holy Ghost is "a foretaste of eternal joy and a promise of eternal life (page 65)." Who does not want to have those blessings? Having the spirit with you is the best way to remember the reason you are here on earth; to return home to your Heavenly Father.
I want to bear my testimony that living so that the spirit can be with you is vital to your happiness now and for the eternities. I know that the Holy Ghost is there to help us return to our Heavenly Father; that is why we are given the gift of the Holy Ghost when we are baptized. If you have made choices that make the companionship of the Holy Ghost less of an option, I know that you can change your life so that the Holy Ghost can always be with you. Not just sometimes, but always. Change is always possible because of Jesus Christ and you will be blessed for it with the companionship of the Holy Ghost to help guide you home.