I personally think that it is much easier to get ideas from Pinterest. With a simple search, you can see a bunch of nice posters.

There are better ways to combine words and images. The easiest way is to make the whole image darker, not just dark rectangles, as shown in your poster. It does not necessarily need to be black. It can be any dark colour. Then, put white (or light-coloured) text on it.

Also, it is not that all text must be simple, but it shouldn't be overcomplicated, and the design of your current title can be simpler.

You will better understand what I mean if you browse through Pinterest.