'The statistics' seem to be unanimous that it has become ever more difficult to gain Christian converts among Western populations. None of the denominations are succeeding - not even those that were until the past few decades successful and growing - and all are losing more people than they gain, all are shrinking and some rapidly.
[This shrinkage may be disguised by the recruitment of recent immigrants - but this is not the point at issue which is about The West, immigrants do not replace natives in structural terms, and anyway such apparent gains are usually very temporary.]
This decline in the effects of conversion efforts is confirmed by my social interactions and personal observations since I belatedly became a Christian (one of the exceptions!) some 13 years ago. Nowadays, people cannot or will-not believe in God, Creation or the promises of Jesus Christ.
What can we do? We can continue flogging a dead horse - like Western missionaries and the evangelically-minded have been doing for the past generation. Using the same arguments and tactics with less and less effect...
Well, since I believe that we finally decide upon salvation only after our biological-death; we could work on that post-mortal decision, rather than on what people can or will do here-and-now?
Rather than working-on what 'is'; we might instead discuss what someone would ideally want for himself, if it turned-out to be true.
Something like: "Supposing Resurrection into Heaven turned-out to be true, and you discovered that it was true after you died; then would you want it?"
In other words, the person might be invited to 'rehearse' the decision he will have to make - and to think about what he might ultimately and ideally want for himself and/or those he loves (even if, at present, he regards it as false).
More generally; he might be invited to imagine what it would be like if some Christian claims we in fact correct - how would he think about it? If there was a personal God who created this universe and loved us each as his child?
Would such a situation of meaningfulness and purpose and eternal relationships be preferable (or not) to the prevalent idea of all reality - and our-selves - being accidental, pointless; going-nowhere but oblivion; signifying nothing and all our deepest relationships as merely an instinctive blip coming from and disappearing into a void?
Perhaps by asking what people want, and which possibilities they would prefer to be real, minds may be opened to that ultimate and unavoidable decision for which we are all and each responsible.