Can vary based on the Channel, it's type of content and how easy or hard it is to make, your internet upload speed which can really hold you back based on your file size and then what you can actually fit in time wise.
I try to do 3 a week minimum but I do have upload speed issues but I am currently doing Homefront The Revolution, DOOM and Fallout 4 DLC's but have 2 other games that are coming out soon that I will also be doing 1 a week of so got to try fit in 5 uploads a week I have to get real proactive.
Upload a few hours before your traffic peak on the real-time graph.
That way you are positioning right in front of the wave.
Add the new videos to all videos cards to highlight it, and set it for "returning subs" and "new visitors" to see.
If you have a marketing budget, allocate $5-$20 for Adwords to it.
Share it across the web if you have an active engaged following somewhere hungry for your content, or you have identified other places your audience hangs out and are willing to hop over to Yt or watch it embedded.
Sometimes your can't see your videos within your 24 hour upload cycle. It may be best to upload every 2-3 days. Only way to know is to experiment, daily, 2 days, 3 days, see the stats.
That's the best way to give each video a chance to succeed.
I currently upload a video a day, but plan to upload two a day starting this week! Upload at least once a week. I think it is the best to upload at least once a week. be as consistent as possible. You don't have to upload everyday. For my time of channel and my life in general, I choose to.