First step is to get your inspiration. You might think graphic design is so difficult, but to be frank, we all copy basics from around the internet. Backgrounds and icons are something very time consuming to create from scratch, and the moment you edit and/or ad-on in Photoshop, there are no copy right applying anymore!
You might already have a theme or design guidelines to follow, so take 20 min to search google images for inspiration.
2. Youtube Youtube Yourtube
So now that you have a few images that you would like to use elements from, to create your banner/flyer/posts, you to go Youtube to find a tutorial how to make it happen in Photoshop.
If you want to create a watercolour background, there are plenty of videos which show you step by step, how to create watercolours. You can basically find EVERYTHING on youtube and this is where we learn new tricks from, everyday as well.
If you don't have time to create your backgrounds from scratch, you can use websites like www.freepik.com
where you can download all kinds of graphics for FREE.
3. Size & Setup
So when you are ready to start making your creatives in Photoshop, you want to get the settings right from the start.
If you will use your creatives for online marketing, you should choose 72dpi and if you wish to print it out, you should choose 300dpi.
A standard flyer for web is about 600px by 900px and for print you can use either A5 or A6.
As per the size of your online banners, please see below image:
Remember you are working in layers, so background is lowest and then you build your way up. Add text layers with different fonts and customise the size, thickness and colour as per your wish!
If you wish to add an image, you can drag it directly into your Photoshop worksheet, for an easy and fast way of working. Mark an image- or a text layer, click on the eraser icon followed by a random click on your sheet, to rasterise
it. Now you can erase and edit the shape of the image or letter as you wish. cmd+T gives you the option to transform the shape as well - Right-click to get more transformation options!
When you are ready to save your masterpiece, you save it as a photoshop file in File/Save As and to save it as a picture, you choose File/Save For Web, where you can choose either JPG or PNG.