1. To make this sound, the tip of the tongue touches the gum ridge behind the upper teeth and stays there, then let the air stream flows through the sides of the tongue. If you don’t know where the gum ridge is, try to say like, look, luck, loss, unlock, or 来，路，罗，郎等. When you say these words, the place your tongue touches is the gum ridge.
But remember, the /l/ sound is just one singular consonant sound, not le, or la or something.
2. Most Chinese students don’t have a problem with the /l/ sound when it is in front of a vowel sound, as in like, look, luck, loss, unlock, collect, etc.. It sounds exactly the same as it sounds in Chinese(来，路，罗，郎等)．
3. When /l/ is in front of a consonant sound instead of a vowel sound, Chinese students tend to miss it. For example, could you distinguish the differences between the pairs of words below?
word & world, code & cold, toad & told, debt & dealt, wide & wild.
To solve this problem, when it’s time to say /l/ in these words, the tip of your tongue should touch the gum ridge and make the /l/ sound, before you pronounce the following consonant. Try it again. See if you can find any difference.
This is the one of the most difficult sound for the Chinese students. Practice these words and try to find and remember the difference:
milk, felt, difficult, old, gold, sold, build, wealthy.
4. When /l/ is at the end of a word, like will, people, Bill, tell, etc., don’t add an extra vowel after it(will is not willa or wille), nor make it sound like /O/ or /w/(people, not pepo; bill, not bio).
To make the correct sound, also put the tongue in the right place which, as we said before, is the gum ridge. Make the /l/ sound. Don’t add any extra vowel sound. Don’t round your lips.
Put your tongue in the right place. Keep practice. It’s not so hard that you couldn’t make it.