It might help if you gave some examples. Most people have very thin skin and their egos are easily bruised, so yes they probably do want to tape up your mouth, hahaha. First of all, you have to ask yourself, do I need to be right and that is why I won't let a subject go? If so, then you need to work on the need to validate yourself through your opinions. To me, it sounds like you just have a case of nerves. Before you say something, if you can, try thinking "If someone said this to me, how would I react?" If the answer is badly, then I know you know what to do!
You should drop a subject when you realize that you 1) either realize that that subject makes her uncomfortable 2) realize that neither of you can peacefully have a difference of opinion on that matter 3) she knows nothing about it and her eyes are glazing over 4) She finds it offensive. That's a pretty good indication. You might try introducing subjects that you're unsure about slowly and see how she responds to it before you get in too deep. Hope this helps!
Listen! The most basic advice to get and the absolutely hardest thing to do ;) If the subject is too awkward you'll notice if you really pay attention to her. She'll for example maybe look away from you, and hesitate before she answers, or just stay silent waiting for you to drop it.
Also when you say something stupid, acknowledge it instead of trying to hide it! Make it into something funny or self ridiculing instead of awkward and switch subject, most girls will appreciate both the humour and the getting-rid-of-weird-situation. Dispell the awkwardness by saying, "oh man, that was stupid now I'm switching subjects. Do you like cheese?" (extra points if she knows the movie the cheese reference is from ^^ If you wanna ditch the it just substitize cheese for ice cream or something), or "That was really out of orbit, I need to get back to earth now." Or you could say "I'm just noticing this is really awkward, don't you think?" Takes away a lot of tension just to mention that it's there.
Just noticed I'm on a whole different page from dsc2222 ^^ But we both have sound advice, just check for what applies the best to your situation :)
Haha cute. I am really flattered when a guy I like just can't keep it together when he's with me. When you think you just said something stupid, say something about it. Like "does that sound really dumb?" If she likes you, she'll be like "No no! It's fine!" hahaha
Be responsive to your date and pay attention to the signals she is giving off in her body language and speech. Women love to talk, so if you struggle with conversation make sure you have plenty of questions to ask and let her do most of the talking - she'll feel like you've taken a real interest in her and the majority of women really value listening skills in a partner.
a lot of us are awkward too,so some might understand your awkwardness. it can even be kind of endearing. if you want to control it-don't blab-take your time,think about what you're going to say,and don't feel the need to speak just to fill a silence.
Just relax and be yourself. If you screw up or say something stupid make a joke out of it or start laughing and say something like "Do you think that's really stupid" and just laugh it off and change the subject. You'll be fine from there :)