For the closure part, just imagine getting your speech articulators into position for that speech sound. That's all you should be focusing on for the first step of "closure". Say for example a 'b' sound. Think about how a b sound is made. What's the required starting mouth position for making the b sound? In this case, a b sound is made by putting your lips together. Just do that action and forget about anything else. There should be 0-1% tension or pressure in your lips, you're just putting them together with the least tension or activation you can muster.