No.40 - you need to concentrate on the second part of the clue. It's a well-known phrase. When you're trying to do something and getting nowhere, you might as well give up because you're......
Don't forget horse will be in the answer so you can always google 'phrases containing horse'
No.77 - there's an anagram to give the first word, really follow what the first three words say. You will get a well-known race-course. Second word means sailors and altogether if you take this product, you will feel better