No matter what tool you use to design your poster, the first thing you must do is set the dimensions of your project to the final poster dimensions. In some tools (like Canva) you will need to set custom dimensions before creating your poster. In some tools (like PowerPoint) you set these after creating the file.
If you add images and content to your poster at default dimensions like 11" x 8.%", then expand to 48" x 36" at the end your poster can become to blurry to read.
Confirm the poster dimensions with the conference you are presenting at.
Most design tools have a feature that lets you turn on grid lines to help align your text and images. This will help you keep your poster aligned. You should also look for the alignment tools in your design tool's menu. These can help you line up groups of text boxes so that they are centered on top of or next to each other.
You can turn these off later when you want to preview your poster as it will actually appear.
Grouping content is very helpful when you want to move more than one element on your poster but keep original spacing, formatting, etc. To group content like shapes, charts, and text boxes you can:
If you have an image or text box that you'd like to equally size (i.e. keep original proportions but make larger or smaller) click on the element, hold the Control key, and size the element with your mouse.
If you need to minimally move content, you can use your keyboard instead of your mouse. Just select the element and use the arrow buttons on your keyboard.
To duplicate shapes, charts, and other elements, use the keyboard shortcut Ctrl + D.
You can find simple Poster Presentation templates freely available on the Internet. If you'd rather use a template, go ahead! Remember to double check that the size of the slide is correct before you begin adding content.