Think before speaking

So, I have a great problem of doing things before thinking. Mostly saying/posting stuff online before thinking, but still.
I recently did this with a friend who I met online and became close with. Well, I hadn't heard from her in awhile and then when stuff happened and she'd post about it, I was annoyed, not so much that she didn't tell me, but more because she hadn't told me in the few months that I hadn't talked to her. So I stuck something up on my blog, that I should have thought about longer and not posted.
That's at least the 2nd time I've done that. Sometimes I should just write the post, but wait a couple days to post it, because of things that you learn, and that your mood levels out in a few days.
Something else I should have thought about more, but still love, is my last tattoo. I have 3 tattoos, one: my display pic, two: a ring of flames on my arm, and three: the outline of a panther walking down my arm. In the beginning I wanted a wolf walking down my arm, but couldn't find a pic of what I wanted, so finally settled on a panther. Now, I'm not saying I don't love it, because I really do, just sometimes I look at it and think, I should have waited, or at least got it on my leg. My mom has even said she'd pay to have it removed. Now, it's no secret between my parents and I that they aren't very fond of my tattoos, but obviously my mom really hates this one. I actually considered the idea once, but then I researched it and found an outline will still be visible (which is what the tattoo is anyway), and it hurts like 10X if not more than getting it. So, no thanks.