I want to give you some advice but it's hard! How would you like to paint? Is there an example style you would like to do?
For something closer to photorealism I find it's important to maintain very clean edges to create clear separation between the petals, as well as getting the bordering shadow values perfect (not too dark or light).also avoiding all blending other than very careful blending to soften an edge or adding a value in between two to soften it a bit. Seems like you dabbed on colours instead of doing longer and cleaner strokes following edges. That style seems harder to me unless you have high level precision like Mark carder. Anyway these are just some of my thoughts. The flowerrs ive done that look impressive were painted carefully with colour checking and a tiny brush. Flowers are hard to do with bigger brushes because flower petals are small and require precision
The lighter values are pure phthalo blue and white and adding a bit of ultramarine is enough to make them much less bright and powerful. Same with the mid range values although those ones also have the magenta in them.
@Renoir thanks I used quinacridone magenta and ultramarine blue and cadmium yellow. Needed to buy a special red for these because the colour isn't matchable with cad red or the geneva red or alizarin crimson.
I'm not totally sure about this, but I think the main reason the flowers still look like "realism" and don't have the more acrylicy look is because I painted them using the right values from dark to light. It might also have to do with oil looking different than acrylic? Either way I learned that I can max out the saturation and brightness and still have it look good