There are many ways to answer this and what suits one person will differ from what another person desires.
That said, a good parish is one where people encounter Christ in each other, in liturgy, in the community, in service to others, and in prayer. They should then feel enabled to respond positively to God and share their faith with others in their daily life, in some way (verbally and/or non-verbally).
A parish should have a sense of communion, which is of course linked to a sense of community. Catholic parishes are therefore often involved in social action projects, working with and for others, Christian or non-Christian.
Material produced in collaboration with the Agency for Evangelisation in the Diocese of Westminster.