Any tips for improving quality of low-res video?

Sometimes upscaling low res video simply does not cut it.

An alternative is to exaggerate the poor quality of the source material and use a Ball Dispersion effect in After Effects to make it appear as a heavily pixelated image (which it actually is), as if you're looking at a screen from a very close up distance.

In the past, I have had to resort to this technique for a promo, where they only had SD quality video for an HD edit: https://vimeo.com/12764462

The technique I used is explained in this ball dispersion video from Video Copilot: https://www.videocopilot.net/tutorials/3d_ball_dispersion/

Hope this helps, if upscaling does not work.

As Jampff suggested 'detail preserving upscale' in After Effects will do a decnt job of upscaling images.

If you have to stay in Premiere Pro, the scaling is not too bad. You could also try a slight amount of 'sharpen' (found in effects) to 'crisp' up blurry images. Don't expect miracles though and 'sharpen' will also highlight any noise or jagged edges in your scaled clip, as you may have found!

There are a number of third party plugins that do better jobs of upscaling in Premiere Pro, I like Samurai from Digital Anarchy. Red Giant have 'Frames'. Boris have 'magic sharp' which is one of my favourites. RevisionFX have SK Sharpen.

At least some of the above companies (probably all) have fully functional trial periods on their plugins - so you can check them out and potentially use them on this project.

All that said, if you are starting with low resolution material, the end result might be an improvement but never going to match native resolution material.

Good luck. 

The only thing I can think of is that After Effects has an effect called "Detail Preserving Upscale"... which is designed to let you blow video up into a resolution larger than it was shot. Instead of blurring/pixelating, it uses AI to draw in the edges/basic details, etc. so that you still get a clean picture (I think). I haven't used it but I saw a tutorial on it recently and filed it away.

I don't think it's meant to be a magic wand. In other words, expect results within reason. If you're enlarging a Zoom speaker in a little tiny box, you may not be able to get the talking head to fill the frame nicely, altough who knows? Worth a try. You should be able to blow it up some though.

Of course, this requires After Effects. Do you have access to it or just Premiere Pro? I don't know of anything in PP that can solve this. The resolution is what it is...

Here's info on the effect:

https://helpx.adobe.com/after-effects/using/detail-preserving-upscale-effect.html

https://www.youtube.com/watch?v=L79FkGC5kvc