Can I become a ghost?

We still have no real idea what a ghost really is but if it is as lots of people believe, a ghost is the spirit of someone who refuses to go to the light. That being the case, just don't go to the light and there you go. As for myself, I think I would be curious as to what is in the light. At the same time, you may be witnessing a glitch in the matrix. If two timelines come close together, you may see people who are alive and well but in their own timeline. You may see a man wearing hansom cab driver garb and although he is alive and well in his timeline, in your own, he will be well dead and buried. That is also another explanation as to why they have clothing.

Ghosts as such are not real, but there are real phenomena we traditionally CALL "Ghosts"---Unfortunately, we do not know what they really are.  The best theory is that they are what we see, should we be looking into a Space-Time anomaly and see a loving human from another TIME on the other side of it.----These anomalies CAN exist according to Einstein and Rosen, and seeing a fully clothed person from another time through it, is a distinct possibility---should the person ALSO be on the other side of it like YOU.---And how many of these HAD no other person on the other side?---likely MOST of them---they are likely more common than we think and we do not notice them---Unless there is someone or something to see on the other side.

This unnerving effect is likely what we traditionally call "ghosts"---erroneously think it is a "Spirit of the dead.

So you might go around looking for such anomaly (Called an "Einstein-Rosen Bridge" or "wormhole") stand in front of it and hope another person from another time or place finds it the same time as YOU---Then YOU will be the "Ghost" to him and vice versa.

You already have a ghost but maybe don't use/be aware about.

No you can't become a ghost since they are not real, maybe you can aspire to be something more realistic.  

assuming ghosts are real I believe the only thing youd have to do is die