You've spent ages creating something lovely ... now you're stuck with a lot of loose ends. What's the best way to secure those threads so that your hard work doesn't unravel? First, you'll need a yarn needle - choose from blunt-ended, plastic or curved depending on your preference - and have a pair of scissors handy.
Then take a look at this great video from Red Heart with Kathleen Sams. It's an excellent starting point with lots of tips.
How to weave in ends after the project is finished video tutorial:
As you'll see in the video, one of the techniques being described is the 'back weave' finish. Basically, you run your yarn behind the stitches of the handiest row, then miss one stitch and run the stitches back again. Missing out a stitch anchors your end in place and ensures that it won't pop out again or, heaven forbid, start to unravel.
There are other ways to keep your ends in place, including whipstitching. While whipstitching is very secure, it is one of the more obvious finishing techniques, so always be sure that you whipstitch on the wrong side of your work, leaving the right side looking perfect. It's also a technique more suited to items like sweaters or hats, where you are unlikely to see the inside of the project. Here's a great illustration of the whipstitch technique from Craftsy with the thread end in pink, so it stands out really nicely against the white fabric of the project and you can see exactly where the thread goes:
One of the easiest ways to keep ends to a minimum in your project is to double up your yarn, so that you take the loose end with you as you work with the new yarn, twisting them together. This is not always practical, though, if you are using a multi-coloured pattern, like a granny square, an Afghan or any item which involves frequent yarn switches. But, if you are crocheting a block colour item like a long scarf, this can work really well and can mean that when you've finished the last stitch, you are actually finished with the project, instead of having to move on to the weaving-in stage.
How to weave in the ends as you go and how to change colors video tutorial:
Some projects, like lacy or very textured crochet stitches, don't really have a right or wrong side, they can look very similar on both sides. With projects like these, you'll have to be very careful to weave through the stitches gently and study the effect carefully before finishing off, so that neither side shows too many lumps and bumps from your woven-in ends.
While there are several ways of losing those annoying ends, there are a few guidelines which always hold true. Try to leave tails on your work that are long enough to weave in for around an inch to an inch and half, and always be careful when you finally take your scissors to that yarn - you wouldn't want to snip your project by accident. You should weave your ends in before blocking a project, as then you can adjust any little distortions or lumps and bumps that may have crept in.
If you have to join pieces in your project with a seam, then this is a great place to weave in any ends as they will be covered up. Also, remember to pull your yarn nice and taut when you finally snip off the end - it will spring back, under your stitches, and should stay hidden forever!