Well, it does help to know what an effect does but some of my best results have been as a result of trying something by mistake or just playing. When I first changed from Photoshop to apps on the iPad I wasn't able to produce anything for the first 6 months and I only really felt comfortable after a year. I couldn't understand why I had this 'artist's block'. I think it's apparent in some of my earlier attempts in my 365 day project where I also express my frustration. Later I realised. I just had no idea what was possible. It was only when I had tried loads of options in loads of apps that I was finally able to produce the same stuff that I had done on Photoshop and better. I could look at a photo and think, hmmm, that's the sort of photo that would look good as a water colour or if I added a bit of Coherence in iColorama that will smooth the edges. The more you know your apps the more creative you will become. Blending, cutting out and masking are really the creme-de-la-creme. If you can do these it takes your photos to another level.
I now believe this principle applies to all arts. That's why it takes time to be a good artist not because we are not capable but the more we play and discover, the more we are able to achieve. That's what I think anyway.
Yeah and I think your example above is a case in point!