How to make good looking Instagram graphics with Canva

I’ve started experimenting with making Instagram posts and I basically have:

a) pics of women (free stock photo)
b) Then I select something called a frame and put it on the blank canvas. This can be like a circle or a square with rounded edges, or some other shape like this:

Then a picture “click into this” and I need to finish the design by changing the color of the background and in the last case also this orange frame.

The thing is that I don’t understand the rules of this and it does not come out good. On the top of that if I make them in different colors (pretty much randomly, checking what looks good and making it this way, and this is not that easy to accomplish too, meaning it would rather look bad, hard to find a good combination of colors) they don’t look good as a part of the overall Instagram feed. The feed becomes like a mess, like I would mix 20 colors together in a bucket and I get a bad looking brown, type of thing.

So I would be trying to find out what rules I could follow in order to accomplish good results, also how to plan a good looking feed, meaning one that looks good as a whole.

I am working on this (the last two are mine and as you can see this is on a path to disaster as far as the look of the feed; also one before the last one looked good but when I added the last one it became worse).

So these type of issues, and trying to figure it out.

Thanks.

This was suppose to be added to the previous post, this is what I am working on: