Nova Flower

Firstly, create your canvas on Adobe Photoshop by pressing Ctrl + N. It can be whichever resolution you like but need to be big enough for the lens flare, I chose 800 x 800. I find it easier to work with a black background colour but you can experiment with different colours.

Go to Filter > Render > Lens Flare…

This window will appear, I have kept the default settings but you can experiment. Don’t click OK yet!

Click and drag the grey cross into the center so that it appears as a glowing circle. Now you can click “OK”. You will now need a new background, press Ctrl + Shirt + N to make a new layout, click and drag this layout to the bottom of your layout order. Then use you Paint Bucket tool to apply a background (make sure the correct layer is selected).

Make sure you have selected the layer with your lens flare. Then go to Edit > Free Transform.

Click and drag one side of your lens flare layer to make it thinner.

Apply those changes and move the thin lens flare to the center of your canvas.

Now duplicate this layer.

Now apply the Lighten blend mode to the duplicated layer. Again, you can experiment with other blend modes.

This time, we want to rotate the duplicated lenses. Go to Edit > Transform > Rotate and drag and click to get your desired petals.

Repeat the Duplicate > Lighten > Rotate steps until you make a flower. You can make as many and little petals you like depending on how many times you duplicate the layers.

Now for the fun part! You can choose any method to colour your petals but for this one, I pressed Ctrl + U for Hue and Saturation, ticked “Colorize” and played around with the colours of each layer. Good luck!

Here's an example where I used this technique