Reverse decoupage - Newbie needing advice

Hi all,

I recently started doing reverse decoupage. I'm a newbie and would like your feedback/advice. On every vase I made, you can clearly see the brushmarks over the pictures I used. (I use Mod Podge). How can I avoid this? Additionally, I don't know how to make my pictures blend in my paint. The cut outs are super visible and often annoying me :-) Is this something I need to 'accept' when it comes to reverse decoupage? Thx!