The Spirit of God speaks to each of us in a different way. I have recently learned that the way I understand the Spirit best is through word and action. In other words, I simply feel that if I follow the Spirit, I am going to do or say something, and that it is right. The first time I remember feeling this way was when I was a teenager and woke up early on a summer morning and simply felt like cleaning the kitchen. So I did. Then my mother came downstairs, exhausted, saying she'd had hardly any sleep and was so glad I'd cleaned the kitchen.
Another time, a woman came in to Walgreens to buy cigarettes. I felt prompted to ask for her ID. She was flattered! It made her day that she looked young enough to be asked for her ID for tobacco.
More recently, I have learned that, usually when I have a calling in a certain area but also with friends, I will simply feel certain words come to me. I often don't know what I'm supposed to say until I say it. Sometimes I struggle with how best to word it.
A word of caution to anyone with my same gift, which is given by God so that we may bless others: just because you feel prompted to say something doesn't mean everyone will listen. They may be prompted to take a different course; your prompting may have been to give them insight, not direction. This happens most often to me when I am giving friends advice. I feel prompted to give them my point of view, which is helpful but not definitive to them.
Remember also that all who do good work by faith, by the power and gifts of God, through His Spirit. These gifts include faith, hope, and charity. They include power unrivaled by any other organization or standpoint. They are powerful and useful in their place. We should "covet to prophesy" (or to speak by inspiration) and "seek after spiritual gifts." The greatest gift we can receive in this life is charity, because it motivates us to be all that we can be, to progress from glory to glory until we are perfect. In the name of Jesus Christ, I bear that testimony, that these spiritual gifts are available unto all who diligently seek them, and they cannot be perfectly imitated by Satan, by tricks, or by psychological wisdom. God alone can grant them. In the name of Jesus Christ, Amen.