Above is a basic Spiral Shape that I drew to demonstrate this technique using the Spiral Xtra. There is also a custom Guide there that started as a basic line then sent to the Guide layer.

What I want to do, is be able to snap the highlighted point shown above to that guide. This would nearly be impossible without the feature I'm about to describe.

Sure you could simply move that guide, but what if there are other shapes using that guide too?

First you'll want to turn Snap to Point and Snap to Guides on under the View menu. It also helps to turn on the Smart Cursor preference too, so you can see the cursor change when you are doing these "snaps."

Above is what usually happens when you try to Click-Drag a point from a shape and snap it to the Guide. This has always frustrated me, and ended up doing some convoluted workarounds to get it to work right.

Now are you ready to see the light?

First, make sure there are no points selected on the path. Then before you click on a point, press and hold the Control key. For Windows users, you have to deselect the whole shape first, then press and hold the Control key.

Now move your pointer over the point you wish to snap to. When you see your cursor change, Click-drag the point to the guide. The whole shape will move with it and you can let go when the cursor shows that you are snapping to the Guide (Hollow dot or Guide Snap cursor).

The thing to remember is to press and hold the Control key first before you try to select any points.

Also, if you don't see the shape's outline while you are dragging, wait a little bit until you see the Four-Way Arrow cursor.