How to make a complex path with circles and pathfinder

Question

So I keep seeing this method of design on sites like dribbble or behance but I don't know how to do it!
Here's an example:
Basically a bunch of circles are used to create this awesome shape and design. I have a general idea on how to use the pathfinder tool and I have used it a lot in the past, but how do you snap circles together with smart guides? It seems that the smart guides only snap based on 90 or 45 angles and don't snap edges of objects together unless there are two anchors.
Here's an example:
I want to use the curves from 2 circle shapes to make a complex path. But I can't get the two paths to snap together
Ultimately to create something like the raindrop image above. I want to use the perfect curves on circles to create more complex shapes but since the paths do not snap together, I'm just eyeballing it to be close enough to do something with the pathfinder tool. I have tried many ways to solve this but I cannot figure anything out.
Kyle

Answer 1

Kyle,
Presuming you wish to move one circle to snap to another circle at a certain predetermined angle, and you have it placed at a distance at that angle you may (Smart Guides are your friends):
1) Select both circles, and with the Line Segment Tool drag a line from centre to centre (Smart Guides say center when you are at the first one and close enough to the second one);
2) Select the circle to move with the normal Selection Tool, then hover over the spot where the line crosses it (Smart Guides say intersect), then ClickDrag along the line (Smart Guides say path) until you have dragged it to snap to the other circle (Smart Guides say intersect).
This works whether the circles are beside each other or one is inside the other.
When moving vertically or horizontally, there is no need for the line, and you can just ClickDrag by the relevant Anchor Point.