Doing a double crochet into a ring is not difficult. In fact, it may be easier for beginners to make double crochet into a ring than to crochet an object that requires you to figure out the right loops in the chain to crochet into. The most common crocheted items that require you to crochet into a ring are granny squares. You can make blankets, bags and many other items with granny squares, either one big square, or many smaller squares sewn together.
Crochet a chain. Your pattern will usually tell you how many chain stitches you need to make for your beginning ring. Generally, rings range from 4 to 6 stitches. Join the first chain stitch and the last chain stitch with a slip stitch. Now you have your ring, and there should be a loop of yarn encircling your crochet hook.
Hold the crocheted ring in your non-dominant hand for stability. Using your dominant hand, twirl your crochet hook so that a strand of yarn attached to the ring lays across your crochet hook from right to left.
Insert your crochet hook into the center of the crocheted ring from front to back, keeping the loop on the hook as well as the strand of yarn laying across it.
Wrap yarn around hook again from right to left at the back of your ring. Pull crochet hook towards you through the ring, catching the last strand of yarn under the hook part of your crochet hook at the same time. The crochet hook should now be at the front of the work again and there should be three loops on your crochet hook. Wrap yarn around hook again, on top of other loops, then pull crochet hook down. Pull hook with last strand of yarn you made through two of the loops. There will now be two loops on the hook. Wrap yarn around hook again and pull the hook with that loop through the last two loops. There should now be just one loop on the hook again, and your double crochet into a ring has been completed.
If you're new to crochet, you may want to practice crocheting into a ring with waste yarn instead of the yarn you plan to use for your project. That way, if you have to rip it out and try again a few times, you won't make your good yarn threadbare.
Make sure to use the correct size hook for the yarn weight you are using. If you're not sure what size is right, consult the yarn's ball band, which will usually give you and range of what size hooks to use. For example, for a worsted-weight yarn, you would likely use hook size 6 to 8. For a bulky yarn, 10 to 10 1/2 would be more likely.