With regards to serving in the church, first, we just need to be asking the question: How can I be a blessing to someone? And then here’s what we need to understand: If you serve and meet a need in such a way that another is encouraged or edified and God received the glory, then the Spirit was at work. Because the Spirit doesn’t want to conceal your understanding of his gifting, eventually it will be made clear how you are uniquely gifted to serve the body as the body is consistently edified in your area of service.
Along those lines, consider this: No church in the 1st century had a spiritual gift questionnaire, but they still were able to somehow to discern who had what spiritual gift! It follows that the Spirit made it obvious who was gifted in what way or ways. In doing so, it seems that there is an internal verification and an external one and both are necessary. In terms of the internal verification, there is a measure joy that will occur while serving, which certainly does not mean that hard work is absent from the equation, but rather we can readily discern God blessing our efforts. Along with that, as already mentioned, there will be an external verification in the form of the body’s positive feedback. It goes without saying that if the body is never or rarely edified by your service, then you’re not driving in the correct lane of service. So, the Spirit working in one’s heart and in the body of Christ are all the verification anyone needs. Thus, according to what Paul teaches in 1 Cor. 12, this is how the body will function properly with each member doing its part.