You should not join a church whose doctrine falls below a certain level of accuracy or specificity. On the other hand, doctrine is by no mean the only concern, and just because one church's doctrine is better than another's does not mean you should go to it. Many other considerations enter too.
We tend to ask ourselves, ``Does this church fulfill my spiritual needs?'' or, thinking we are being virtuous, ``Does this church fulfill the needs of my children?'' Both are selfish questions, even though they have some validity. Rather, ask what you can do for this particular church. Do you fill a gap? Do they have a need for you, and, a separate point, will they allow you to fill that need?
This is a selfish question, but it is still worth asking. Will you be challenged? Will you be taught? Will you worship God well? Are these true for your family also? Can you bring nonreligious friends and have them benefit?
If it is too rarely exercised, that is a sign the church is antinomian, whether it claims to be or not.
If there is no directory of members, or even a directory without photos, that is a sign of lack of community and caring for one another.
In particular, who is excluded by the vows? If nobody is, then they are meaningless as far as belief goes. Also, what obligations does membership entail? If none, then membership does not mean much as far as one's life.
This is related to the membership vows. Some churches are too exclusive, and some too inclusive.
If it doesn't have a web page, or does not update it, then the church is poorly run. It does not care about easy ways of reaching out to other people or informing its own members about what is happening, and if it does not update the web page, it does not care about conveying false information to people.
Where money goes, there look for the heart. Also, avoid any church that does not release its budget to the public; they're probably misusing funds.
If so, the church is in decline and has lax membership standards in practice.