https://ladysilvertongue.tumblr.com/post/174787760875/create-your-own-seamless-patterns-in-photoshop
Create your own seamless patterns in Photoshop
This little tutorial will help you create your own seamless patterns from scratch. It’s easier than it looks, I promise. I’m including a floral shape palette that I made in Illustrator. You can use this .psd to follow the tuto and/or in your own creations or CC making or recolors or whatever your heart desires. A shout back is appreciated but not required.
Enough talk and let’s start:
Note: the shapes are inside folders in the layer panel, with labels for easy access. If you’re handy with PS and prefer to use them instead of loading the shape palette, skip to step 8.
Open the shapes palette, click on the shape you want to create, hold shift and drag in your artboard. You will see that a new layer was created in your layers panel. If you want to create a new shape, de-select all layers or create a new one and repeat the step above. If you create a new shape while a layer is selected, if will place your new shape inside and while this may be good for some kind of work, for patterns, where you’ll be repeating, copy/pasting and resizing shapes, it’s better to create in a new layer.
Keep doing the above step until you have all the shapes you want to use in your pattern.
To change the color of a shape, double click the shape in the layers panel and select a new color in the Color Picker window;
Start placing the shapes in the artboard. Don’t place things to close to the edges and nothing should go over the edge; keep repeating and using various colors and sizes until you happy with the look.