If you are un-spiritual by nature, and (yet) want to become religious; especially if you want to become a Christian - the traditional approach would be through reason and evidence - but this may be a mistake.
The best approach - even or especially for un-spiritual people - may be to seek personal revelation and personal miracles by prayer and meditation.
The traditional approach to conversion would be to argue that Christianity is reasonable, has evidence to support it, and overall is the best decision. The trouble is that the process of arguing, gathering evidence, asking and answering questions, seeking clarification, weighing up pros and cons... can go on for a very long time.
In fact the process can go on for a whole lifetime and still not have reached a conclusion. Reason and evidence seldom clinch matters.
Even worse, the reason-evidence process may lead to a conclusion that Christianity is true, but this belief carries only the feeblest of conviction. Belief in it is no more compelling that belief in some scientific theory, or some particular interpretation of the historical record - which is to say these are merely hypotheses which we are happy to entertain, but not something to which we make any kind of deep, lasting, or transformative commitment.
The key is to acknowledge that personal conviction - not reason and evidence - is the bottom line.
So long as there is plausible reason and some evidence to support our belief, that is sufficient - always has been, always will be.
Life is not, cannot be and indeed should not be 'put-off' until some in-principle impossible standard of overwhelming and unopposed proof is attained. Our fundamental beliefs are something that we must feel as warmth in our hearts, grasp with our hands, and which moves us at 'gut-level'.
Therefore we must seek the answer by praying for personal revelations, communications from God; praying for miracles in our own lives; and by meditating to hear the answers and perceive the miraculous happenings.
We must ask, and ask; and must listen for, and listen to the answers.
But what of those people who are too stolid, too common-sensical, too literal minded, too unimaginative, too rationalistically-skeptical - people who have not a spiritual bone in their bodies...
The answer is that these are the exact people for whom revelations and miracles are the most effective, and such people (among whom I number myself) have a strong track record of being granted precisely these gifts, and finding them compelling in a way that nothing else has been or could be.
All such people need to do is firstly to give themselves a chance.
Set aside time for prayer, for meditation; time alone; unstructured and undistracted time - private time.
Make an effort.
Secondly they must not talk about what they are doing with other people, and especially they must not discuss any revelations they receive, nor should they discuss any miracles which happen to them.
Revelations and miracles are personal - they are for you and not for other people; they are given to convince you, and to give you faith and sustain your faith - revelations and miracles are not given to become public discourse, to be picked-over, critiqued, analysed, explained and explained-away or mocked by other people.
Revelations and miracles are not to serve as an argument for your new faith, nor are they to impress other people, nor are they to convert other people, nor can they or will they convince other people of their validity: they are for you and nobody else.
All you can and should do is state clearly and firmly that you have had revelations and miracles which have convinced you - that is enough, and it would be unwise to say more.