V.W.
You can't "get him to see" really. He has to figure it out on his own. Yes, this is very age/developmental. My son is 13 and I was SO frustrated with him in 6th grade. (We still have our moments, lol). But, he really is a super kid. I get compliments all the time. I spoke with many of his teachers in person and on the telephone when he was in 6th grade, because I was concerned about this or that, but every one of them reassured me that it is VERY typical for the age. So try to keep that little bit of info thumbtacked to the front of your brain.
He isn't really TRYING to be difficult or do the wrong things, but his brain is going through some serious development (seriously, read up on the development of the teen brain), AND his hormones are whack, AND he probably is hitting growth spurts in jumps and starts, AND his friends at school are all changing and moody, too.
He is testing what he can do, and he is testing what he can get away with, and how it feels if he does/doesn't get away with it. Realize that. But he will still test. No matter how much talking you do. I'm not saying not to talk to him or that it is not helpful....just don't expect it to necessarily change his behavior. When lying has some real and painful consequence for him (I don't mean a punishment from you either, I mean where it really hurts--- you no longer trust him, his friends lose trust in him, somebody stops hanging out with him b/c of it, a teacher accuses him of something that he didn't do b/c they know it is par for the course with him.... THOSE sorts of things will have an impact. And he will figure it out.
Keep talking with him, point out the longer term ramifications of what he might be doing, or be tempted to do (now or in the future) and get him started thinking about how he will feel/manage it if/when it does... 'You know I am disappointed that you didn't tell the whole truth about _____. It makes me sad that I am beginning to wonder how much I can trust you. You DO realize, that trust is something that can be thrown away very easily but be VERY difficult to regain? Sometimes people NEVER are able to regain full trust in people, when it has been broken. Do you want your friends to believe you when you say something to them? (yes). Do you want your teachers to always assume what you said is NOT the truth first, and have to be proven wrong EVERY time? (no!) Eventually people will stop assuming you are honest from the start, and will start assuming you are not. Like the boy who cried wolf. Eventually no one paid any attention to what he said, even when it WAS true. That can happen with teachers, with friends, and yes, even with me and Dad. I want to always be able to trust you. Even if you make a mistake and do something wrong, or don't do something you should have done, it is more important to me that you are honest about it, so that I can always trust what you tell me."
Granted... you can run into the "speech" mode and they tune you out.... but, I also believe, truly I do, that if you make the effort to GIVE the speech, that even if they tune you out, they GET that what they do and who they ARE, MATTERS to you. That they are IMPORTANT to you. And THAT sticks with them... even if they don't 'hear' a word you have said.
Hang in there.... I think it gets easier....