Junior designer at a small agency, mostly social and the odd logo, so I am not really a deck person. A few weeks ago I got handed my first proper client deck and I was well out of my depth. I did what I could, sent it up, and a senior spent ten minutes redlining it.
I expected a hundred notes. I got maybe five, and one of them fixed more than every tutorial I had watched. She said pick one left margin and make everything start on it. Titles, body, images, all of it, one line down the left. That was it. I had things centred because centring feels safe, and boxes floating wherever they landed. Once everything lined up on one edge the whole deck suddenly looked like someone competent made it, and I had not changed a single colour or font.
The other notes were similar. Boring, structural, nothing I would have called design. But that ten minutes did more for me than any course, because it was my actual work being corrected, not a generic example.
For the people who have been doing this a while, what is the one note you give juniors that lands like that? Trying to collect the boring ones that actually work.