God has given us all certain gifts—gifts to be used for the glory of God. Rather than talk about the nature of those gifts, I'd like to talk about a concept that appears along side them in the Bible: the body of Christ.
Now there are various kinds of gifts, but the same Spirit. There are various kinds of service, and the same Lord. There are various kinds of workings, but the same God, who works all things in all. But to each one is given the manifestation of the Spirit for the profit of all. For to one is given through the Spirit the word of wisdom, and to another the word of knowledge, according to the same Spirit; to another faith, by the same Spirit; and to another gifts of healings, by the same Spirit; and to another workings of miracles; and to another prophecy; and to another discerning of spirits; to another different kinds of languages; and to another the interpretation of languages. But the one and the same Spirit works all of these, distributing to each one separately as he desires.
For as the body is one, and has many members, and all the members of the body, being many, are one body; so also is Christ. For in one Spirit we were all baptized into one body, whether Jews or Greeks, whether bond or free; and were all given to drink into one Spirit. For the body is not one member, but many. If the foot would say, "Because I’m not the hand, I’m not part of the body," it is not therefore not part of the body. If the ear would say, "Because I’m not the eye, I’m not part of the body," it’s not therefore not part of the body. If the whole body were an eye, where would the hearing be? If the whole were hearing, where would the smelling be? But now God has set the members, each one of them, in the body, just as he desired. If they were all one member, where would the body be? But now they are many members, but one body. The eye can’t tell the hand, "I have no need for you," or again the head to the feet, "I have no need for you." No, much rather, those members of the body which seem to be weaker are necessary. Those parts of the body which we think to be less honourable, on those we bestow more abundant honour; and our unpresentable parts have more abundant propriety; whereas our presentable parts have no such need. But God composed the body together, giving more abundant honour to the inferior part, that there should be no division in the body, but that the members should have the same care for one another. When one member suffers, all the members suffer with it. Or when one member is honoured, all the members rejoice with it.
Now you are the body of Christ, and members individually. God has set some in the assembly: first apostles, second prophets, third teachers, then miracle workers, then gifts of healings, helps, governments, and various kinds of languages. Are all apostles? Are all prophets? Are all teachers? Are all miracle workers? Do all have gifts of healings? Do all speak with various languages? Do all interpret? But earnestly desire the best gifts. Moreover, I show a most excellent way to you.” (1 Co 12:4-31 WEB)Our gifts (whether they be spiritual gifts, natural talents, or acquired skills) come from God, just as our very life comes from God. As part of the body of Christ, we are supposed to use our gifts in service to God. But, that's where it gets complicated. Who defines what is the proper service in which to use our gifts?
It's been my experience that when someone (particularly someone linked to a church) is part of a ministry, the right “service” is always their ministry. Even if your gift doesn't actually fit, it's close enough. They often put tremendous pressure on people to join their ministry, but that's not how a body works. The foot doesn't tell the hand what to do, and just because they desire to use your gift does not mean you should give it to them. You need to think long and hard about what God wants you to do with your gift, and then use that gift the way God intended you to use it. Which may (or may not) be in someone else's ministry.
No is a good word for Christians to learn. There is nothing unchristian about telling someone no. In fact, often the only way to protect your mission (the one God gave you a gift to fulfill) is to tell someone no. Otherwise, you will spend inordinate time fulfilling someone else's mission, while yours lies fallow.
The book Boundaries: When to Say Yes, How to Say No to Take Control of Your Life contains good information on how to protect yourself from people who would pressure you into getting involved in their project. It is written from a Christian perspective. When I Say No, I Feel Guilty is also a good book for learning how to take control of your life. I consider both of these books to be required reading.