@catsitter As you’ve said earlier though, you were slow to accept. Putting myself in the shoes of the owner, that likely made them anxious. Most owners want to secure their sitter as soon as possible. It’s unfortunate that you had to learn the importance of quick responses the hard way.
As for looking for August sits, perhaps embed your sitter profile in your forum username/profile. Owners will be able to review it, and all forum members can give you constructive feedback on your profile. 
Also consider setting up saved searches for areas of interest to you, if you haven’t already done that.