People often find dates difficult, especially with all the /θ/ sounds in ordinal numbers. For this, and /ð/ in”the”, it’s important that your tongue touches your top teeth. Teachers often tell students to stick their tongue out, but this is wrong, as you touch your teeth with the wrong part of your tongue, and it makes it more difficult to speak. It should be the front of your tongue, so that just the very tip might be visible if you look in the mirror, but definitely not sticking out. When students make these sounds wrongly, though, it is almost always because the tongue is too far back, giving /t/ or /d/. The difference between the sounds is that /ð/ is voiced, but /θ/ is unvoiced. Remember to say the phrase slowly when you’re practising. All my pronunciation workshop students want to speak too fast!