I'm looking for poster templates to promote my brand's sale online. I've also checked some online graphic design tool that allows customizing pre-designed templates easily. One of them is mentioned below: https://photoadking.com/ Would it be worthwhile to download an online graphic design tool to create posters?
Start with a market survey
Make visual choices to key design and marketing elements
Play around with variations
One of the most effective tools you can use for branding your business is through a logo, brochure, website, etc...
Try using Canva or Pic Monkey to create your own fancy marketing materials
I'd recommend using Canva to start. It offers a great deal of flexibility and stock photos, iconography, and templates to use for even the most aesthetically challenged individual. (:
Plus, it is CHEAP! My team usually ends up using it for most graphic needs on social, internal communications, and event collateral instead of something from Creative Cloud.