Devadolly, here's some help with the two important clues. This is just for you to answer them, the thematic stuff will follow.
37. Last bare layer's very pale. 'Very pale' is the definition. The 'layer' is the frequent three-letter word, 'last bare' = you need two letters from 'last'. This 5-letter word then has to wander, alter slightly - it joins up to the fourth letter in 30 D. 38 A is even more straightforward - a 6-letter moulding, obtained from anagramming most of the next two words in the clue. The answer itself is then anagrammed to give a thematic 'partner'.