Step 2.1-The damned machine

To make a good plan, one needs information, and since we have the internet, information isn't all that hard to acquire.

So, let's start with the most important stuff first. Cells keep on dying. Every day, every hour, every second some of your cells die. There are a lot of them, many, many billions for sure, but if no new ones were born every so often I'd wager we would not live very long.

And indeed, it looks like cells divide through a process named mitosis that basically means making a clone of themselves. 

This is a very complicated process, this cloning stuff, so complicated that even the cells themselves fuck it up every so often. 

Think of it as the clone being a bit dumber than the original. It's still mostly identical, so nobody cares, but then, the clone makes a clone as well, which is even dumber....and this repeats until some clone goes insane and turns into a supervillain (cancer) or the clones end up so dumb that they can't really do anything anymore.

There isn't really a way of simply preventing cells from dying, but the next best thing is stopping the constant degradation each cell generation stuffers.

That sounds like a job for genetic engineering.