The clean corporate look looks simple but is complicated to achieve.
Some guidelines to follow:
Clean: at least 60% white space. Sans-serif font. Few illustrations or decorations. Flat solid color backgrounds. Gradients and shadows kept to a minimum. Everything aligned.
Achieve information hierarchy with type and position- drive attention by putting what you want them to read first higher and in a bigger font.
Use 1 font but drive attention with size color and weight.
Make no titles or text 100% white or 100% black. Use colors and greys.
Color choice is very important but I can't explain it easily. There are many corporate color pallets available online.
Look at many examples of corporate presentations and Ted talk graphics.
Set up a theme and style to use on all conference artwork.
In a sense the corporate look is sophisticated, high brow, simplistic and snooty.
We've all been exposed to it so much that it is easily identified and it's easy to tell when it's wrong. If something looks goofy or messy or too cute or complex then lose it. Simplicity is key.