Adafruit's Guide to Excellent Soldering is a great next step if you want to learn to get really good quality soldering joints, and to learn to use headers or other fancy attachment methods.
Colin's Lab - Soldering is another wonderful guide, featuring some very well explained and enjoyable soldering tutorial videos.
S is for Soldering is a great intro video if you're looking to get young makers excited.
Make It Glow - Your First NeoPixel Project is a great place to start if you're not quite ready to pick up that soldering iron yet, or if you're working with kids. You don't need to solder to use NeoPixels!
We've added links to lots of great beginner projects in the sidebar. Treat yourself and get inspired!