Most "Learn To Draw" lessons look more or less like this:
Draw a circle for the head and a line indicating the curve of the body
Add a rectangle for the body, and some triangles for ears and stuff
Fill in the rest with dog parts, shading and whatnot
I wish I could be more helpful on specifics but as an artist I'm basically somewhere between Step Two and Step Three, and to be honest, my circles from Step One usually aren't all that symmetrical and my lines aren't straight.
I think the key to being a successful artist, though, is the same as being a successful writer or baker or anything else ... and that's not to be afraid or embarrassed or discouraged or anything else other than operating under the assumption that you are the greatest artist on this entire planet.
Even if you really are terrible (which you're not, you're the greatest artist on this entire planet, remember?) there is no other you.
Be persistent in your practice and you WILL get better.
The less you practice the longer it takes.
There's no magic here. Just hard work.
So since this post is called, "How to Draw a Dog" I suppose I'd be remiss if I didn't actually do that. So here you go. Follow along with this How to Draw a Dog video by Christopher Hart. He is amazing and I recommend every YouTube video and book he has. You will pick up so many skills so quickly it will make you dizzy.