It is easy to become a theist (a believer in the reality of 'god' - not specifically nor necessarily the Christian God). Indeed, to be a theist is the only coherent system of belief - as has been clear since ancient Greek times.
1. Recognize the reality of transcendental values - any one from the list of truth, beauty and virtue. Recognize that these are not only a matter of opinion.
2. Recognize that there must be a god/s, or else transcendental values could not be real and we could not know about them.
3. You are now a theist.
4. Recognize that there must logically be one god above all gods.
To become a Christian involves another set of steps:
1. You need to make a decision about revelation.
You need to decide if it is possible that god communicate with humans (divine revelation) or not. This is something to do with whether god is a 'personal god' - who is concerned with humans in general, and in particular.
If revelation is impossible, then knowledge of god must be inferred from the world using reason and instinct - this is the pagan position, natural religion, spontaneous religion in its various specific manifestations.
2. If you regard revelation as possible then presumably it has happened, and you need to evaluate human history on the basis of sorting-out which of the claimed revelations of god are real; and how accurate are these reported revelations.
3. There are not many, three or a few more, major religions based on monotheism and revelation - how to choose?
Find out about Christianity - which is not easy because of the vast amount of disinformation, misunderstanding, and corruption. Then decide whether Christian revelation is supported by, is consistent with, the evidence - prophecies and their fulfillment, miracles etc.
4. If you find that you want to be a Christian, then you should decisively acknowledge this fact to yourself (and others whom you trust) - don't conceal it, don't lie about it.
At this point you have crossed the line.
By clearly acknowledging that you want to be a Christian (that you are a 'seeker') then you essentially are a Christian.
(Because of the promise that he who seeks will find: will find. A promise from God will absolutely certainly come true - because nothing can stop it.)
5. What follows is a lifelong search to understand and know and practice Christianity.
People naturally focus on this final step, step 5 - with all its worldliness, its inter-denominational struggles, failures and compromises and corruptions; but really it is step 4 that is crucial to salvation.
If you sincerely want to be a Christian, you should regard yourself (in private and in public) as a Christian: because in fact you are a Christian.