In most of the crochet patterns that I write, I include some variation of these instructions: "weave in your ends," or "weave in your loose ends," or "weave in any remaining ends." It's important for every crochet enthusiast to know how to do this, so we'll start off with instructions for that first.
Sometimes, I find that weaving in ends can be sort of meditative, the same way crocheting a project is. But more often, I find myself with such an impatience to be done with any given project that I feel annoyance at having to take the time for weaving in all the loose ends.
I know I am not alone in this.
So with that in mind, I'm also going to share with you all the techniques I know about for enabling you to avoid that task, or at least, minimizing the amount of loose-end-weaving that needs to be done. There are many things you can do to avoid having to deal with bunches of loose ends when you're finished crocheting a project. Some of them take a little pre-planning, but once you learn how to incorporate that into your crochet process, it speeds up the finishing noticeably on certain projects, particularly ones that have lots of color changes.
In this video, you'll see a demonstration of how an experienced crochet teacher weaves in her ends on a crochet project.
To accomplish this task, you'll want to have a tapestry needle, a needle threader (optional,) and a finished project to work on. If you gather these things before watching the video, you can try finishing your project right along with the teacher.
Keep in mind that this is one possible way of approaching this task. There are other ways you could approach it; often, you'll find that experienced crocheters have conflicting ideas about the best / most secure / most invisible way to do this. For example, there are people who like separating the yarn plies at the end and weaving those in separately. I don't personally bother with that unless I'm dealing with a really slippery yarn, but it's an idea you could try if you think it would work well for the project you are finishing.
This is a good technique to use with single crochet stitch, or with stitches that don't have a lot of open areas. The technique doesn't work as well with lacy stitches. This works best if you crochet tightly, and might not be a good technique for you to use if you crochet loosely.
In this tutorial, intended to help you with striped crochet patterns, I demonstrate a method for carrying your yarn up the sides of your work. This technique saves you time by eliminating the need for weaving in an excessive amount of ends. Usually, when you use this method, you'll end up with only a few ends at the beginning and end to deal with.
When you crochet granny squares, hexagons or similar motifs, you can use a technique called "join as you go." With join-as-you-go, you'll eliminate bunches of loose ends; this is because each motif would ordinarily have had two loose ends, one at the beginning and one at the end. With the join-as-you-go technique, you don't generate these loose ends to start with, so there's no need to weave them in later.
My opinion: the longer it is that you've been making your crochet motifs in the traditional way, the more of a challenge you might have in breaking out of your old mindset and habits to learn this different way of working. However, if you can just plunge in and do it, I think you'll be really happy that you did.
The page linked above takes you to bunches of resources on the topic of learning the join-as-you-go method. There are free tutorials and patterns available for you to use if you'd like to give this a try. I also recommend picking up a copy of Seamless Crochet by Kristin Omdahl, published by Interweave Press. This is a combination book and CD set, and it's a great resource for learning this technique.
With many projects such as scarves, shawls and afghans, you can transform your loose ends into fringe that will finish off your project. This technique is particularly effective when used with colorful projects, striped projects and tapestry crochet projects.
See an Example: Amy's Scarf of Many Colors (Includes free pattern and instructions.)