More often than desired, clients ask for guidance in doing a project in a way that is “sort of agile”. I do my best to be reasonable, relating to this caution. One of my favorite pastimes in youth was exploring the hills of my native Southern California for new swimming holes. (Yes, there are actually quite a few.) And yet, no matter how hot the day and how inviting the water, I was always slow about getting wet. Somehow it did not suit my nature to just jump in, averse to the shocking temperature difference. For someone new to Agile, the pool can look both inviting and threatening. Even more so if the water is murky.
My usual response is to soften the concern a little by saying that the Agile approach to software development is, well, agile. This means that it can be adjusted to suit the situation. It actually means much more than that – that is can and should be adjusted continuously until it is clearly working well. But many people want to make adjustments before they have tried what I think has become pretty well proven practice. So I suggest starting “by the book”, using the general framework of Scrum and considering some of the XP practices but not necessarily changing everything at once. We Agile coaches and practitioners have probably all seen cases where some mixture of Agile practices turns out to be toxic. More often Agile implementations go well enough but do not achieve their full potential.
Anticipating yet another discussion of starting up a project using a “sort of agile” approach, the following analogy came to mind. I think the teenage boys next door may have had some influence.

Bikes and Skateboards
You ride a bike.
You see me riding a skateboard.
You think it looks like fun so you ask if you can try it out.
But it looks dangerous so you ask if you can take the seat, handlebars and brakes off of your bike and put it on my skateboard.
Sure, go ahead, if you can make them fit.
But what you end up with is no longer a skateboard. And you will not be skateboarding. Face plants may be less likely, but so will jumps . Try a kickflip and your handlebars will get tangled up somewhere unpleasant. Hop a curb and see how that seat feels.
Maybe instead you should get your own skateboard, one designed for beginners. Try it out slowly. Avoid the kickflips and jumps for now. Learn the joy of the ride first, then see about getting fancy. Leave the bike parts on the bike.