I understand your frustration with the multiplicity of denominations and the multitude of contradictory doctrines taught in the different churches. It is certainly one of the characteristics of Christianity as we know it today. Let us consider some factors.
Christ cannot be divided (1Corinthians 1:13). Therefore, there is a unity to all who are in Christ. We visibly see this the most in times of persecution or other trials. However, it is also a spiritual fact. I am spiritual joined to all others who are united to Christ. The many churches and denominations may tend to obscure this fact, but it is still a fact. I have seen this when I have met someone I had never met before and sense that there is something about them. Soon, we each discover the other's love for the Saviour and join in sweet fellowship. This is a unity in Christ that is not removed by the many kinds of churches.
However, there are many distinctions as well. In the passage mentioned above (1Corinthians 1:12-13), Paul is scolding the Corinthians for their divisions within the church of Corinth. They were siding with Paul, or Apollos, or Peter. This is where he pointed out to them that Christ is not divided and that their divisions were foolish. But notice the unity that is being emphasized here. It is the unity within a single church. Although there are exceptions, many of the New Testament verses speaking of unity are referring to individual congregations. Paul does not spend equal time scolding one church for not being unified with another church. He rather speaks to individuals within a particular church. When Paul said, "I beseech Euodias, and beseech Syntyche, that they be of the same mind in the Lord" (Philippians 4:2), he is speaking to two ladies in the church at Philippi. This is the case in many situations. The local New Testament church is an earthly model of the heavenly church which will include all believers. It must practice the unity of Christ.
It is also important to recognize that all divisions are not evil. Titus 3:10 states, "A man that is an heretick after the first and second admonition reject." However, what is to keep the rejected heretic from going down the road and starting his own church? As we know, it is done all the time. I am not evil if I remain divided from this heretical church. In Galatians, Paul spoke of cutting off those who tried to take believers back under the law. From history, we know that these people went out and started their own churches. As the years have gone by and as heresies have proliferated, we have more and more churches--all claiming to be right. It is simply a fact of human nature.
Now, I fully concede that this does not solve the problem of multiple doctrines taught in the different denominations and churches. In fact, knowing the denomination does not always reveal the doctrine of the individual churches. As a Baptist, I am aware of great diversity of doctrine among those who call themselves Baptists. Some are very liberal while others are extremely conservative. Some are Calvinistic while others are fully Arminian in doctrine. Differences in music, standards, bibles, and much more abounds. Though I am a Baptist by conviction, I will be the first to admit many things lacking among the Baptists.
So, that brings us back to the original question: how can you find the right church? Well, as you probably know, you have already answered the question. You must start with the Bible. My own conviction is that the Bible tends to make Baptists out of people. Of course, many others would disagree with me. You will have to seek the truth for yourself and see what the Bible teaches. I am purposefully not making a case for Baptists or for anything else here. It would take too long. However, God is able to lead you in the way He has for you. One thing about it--as a Baptist, I strongly believe in your right and in your responsibility to search the Bible out for yourself and to follow the Lord as He leads you. In Baptist terminology, this is called soul liberty.
