These small errors can be turned into a positive very easily with a sense of humor, a little bit of humility and a desire to make a great impression.
Here are some examples of smaller interview mistakes that you can recover from with the right response:
Mispronouncing someone's name - The second you realize this, you should acknowledge it and apologize. Even if it is at the end of the interview or after the interview has occurred. As payback, tell them jokingly..."If it makes you feel better, you can call me 'Frank' from here on out."
Tripping or falling down in front of the manager - This happens and is the ultimate in embarrassing moments. Get back up with a smile on your face and jokingly ask, "Just checking...is it OK if I wear a helmet for this job?"
Just realizing there is a stain on your shirt/tie/dress - Acknowledge this immediately so that they know you didn't actually choose to wear this to the interview. Then point to it and say jokingly, "As you can see, I busted out my very best wardrobe attire for this interview!" and explain this must have just happened.
Losing your train of thought - Sometimes we get going and talk so much, we end up down a road we never intended to. All of a sudden we are making no sense at all and have completely forgotten the point we wanted to make. Once you realize this is happening...stop! Say something like, "Oh where's the rewind and rerecord button when you need one! Do you mind if I start over here in an attempt to try and answer your question?"
Minor foot-in-mouth statements - You unknowingly oppose something that the Hiring Manager is favorable towards...such as a particular piece of technology, a certain business methodology, a company, etc. By the way, this is a doozie of a mistake which is why we recommend that you never speak negatively about anyone or anything during an interview for this very reason! However, if you do slip and make this mistake, typically the manager will quickly reveal that they feel the opposite way. Don't panic, retract your statement and switch sides (then they won't respect you).
Instead, you should stick to your opinion but attempt to recast what you said be being a lot more objective and and a lot less negative. You can also jokingly say, "Mom always said, if you can't say anything nice, don't say anything at all. Guess I should have taken her advice here! No, seriously though, I didn't mean for that to come off so negatively. What I really meant to say about XXX is this..."
Forgetting your resume - First of all, don't forget to bring one. It can end up kicking the interview off on a bad note. But if this does happen, with the multiple online channels companies have to receive resumes, they should be able to print a fresh one out on the spot. It's a judgment call of course, but if you are left abandoned at the interview without a resume, I'd suggest saving face by telling them you "assumed" they had access to an online copy rather than the, "...whoops, I forgot" response. And if you are an indignant environmentalist, you can always say that you make it a habit never to print things out unnecessarily and waste paper!
I am sure this audience doesn't need the list of "fatal" interview bloopers that you'll never recover from, but here they are anyway just for kicks:
Remember, little bloopers are OK and can actually work to your advantage if you acknowledge them and recover quickly with honesty and humor. This will humanize you in the managers eyes and will no doubt help you make a stronger impression.