When I started writing my first MS I wrote in past tense, mostly. I applied the past tense to my blog, even though it should have been present tense (in my opinion), unless I was actually talking about the past then...oh man, you get my point.
It wasn't until a critique partner of mine pointed out my random present tense slippages and my mild past participle abuse that I realized I even had a problem with tense. Even though she pointed it out, it was very difficult to see and correct. Well I immediately started to focus on my tense and eventually, I mastered it. Sure, in my manuscript I sometimes slip but that's mostly because I'm working through how the manuscript should go. (Too much slippage and I realize I need to change the MS's overall tense. Done that before, what a pain.) Now my blogs, emails, whatevers are in present tense and it makes me feel like I am living in the now.
It feels good being here, present, in the present.
Just another way my writing has changed me.