A very belated review. I apologize for the delay - I was unexpectedly overseas for a chunk of January and missed it.
So first, the very fact that you have embarked down this path is a huge step in itself and I generally agree with Diane and Richard.
To be specific.
Voice. You have already mentioned this but there are a few ways to at least alleviate the problem. Diane is absolutely right that she wants clear instructions and so you are in the right ballpark. A little humor and personality can also go down well and as you get more and more used to the medium you will probably find that creeping in. Don't force it.
I don’t know exactly how you recorded the audio but it sounds like you may have done it separate to the screenshots. This implies that you may have created a script which is a powerful move and gives you a great opportunity for control over the quality of your presentation.
Either way, setting your microphone record level slightly higher will help the softness of the recording. Another and much more subtle tool are headphones. If you can properly hear yourself you will get a whole other sense of how you sound as you record. (NB This may take a little time to get used to!) You also can only really use headphones if you are using a connection that enables you to hear yourself ‘live’.
Every now and then I hear a little ‘pop’ on your voice (e.g. 6.54). This is very minor and infrequent but if you are looking for tips, you will benefit from a pop filter to filter out those ‘plosives’.
You may also find this TNT article useful; http://sbitips.sitesell.com/working-with-audio.html
and there are also others in the audio series.
Beyond that, your instructional video is a very good first go. I’d possibly divide it into two or more sections – eg Basic, Advanced and Expert levels. It feels like you get into some high-tech steps even when you are discussing printing at the end but you will know your audience better than I.
I’m also aware that you are now testing Wistia so if you have linked it to your email (eg Mailchimp) you would even be able to send people advanced videos based on what they have watched rather than including everything in one hit.
Meantime, you can find quite a bit about working with YouTube and getting found here; http://sbitips.sitesell.com/#YTVH
but I think you know that!
Hope this helps and, great job!