Have you ever noticed how quickly people are able to judge your level in a foreign language? Even people who can't speak a foreign language have this incredible ability to classify your linguistic skills. I once had a cat with a Japanese name and when my landlord heard me call the cat she remarked with surprise how good my Japanese was becoming. All I had said was the cat's name! And no, the woman didn't know any of the Japanese language herself.
Most people seem capable of certifying your language proficiency after you've only spoken one sentence. I've had that happen to me many times here in Japan. So what am I supposed to say to them? "Oh, well you're the native speaker so I guess you would know, wouldn't you?"
If you can write your own address in Japanese you are sure to wow them. This is my address, for crying-out-loud! I live here! I'm not a visitor. Do they expect me to be forever illiterate? Have so many of the other foreigners made such a poor impression? It's just a bunch of squiggly lines, so get over it.
Of course, the evaluations will not always be good ones. People who will not be relying on you in any way may rate you extremely high, but those who are thinking about using you are going to be a lot more critical. Whichever the case may be, they are always wrong!
You'll be appraised too high and appraised too low. Your value may be up one day and then completely drop the next. They can't all be right.
So how are they judging you? By reading your mind? No. The assessment is always based upon OUTPUT. Whether it's speaking or writing, it's your output that is being evaluated. As soon as you open your mouth and speak in tongues, their judgment is starting to form. By the time you've completed your first sentence, they have a fully formed opinion of your linguistic capability.
So, if you really care what other people think, you'll be working on your output. There are even, if you can believe this, people who work on their language output from day one! There also exist, people who try to make as many errors as possible when practicing output. OK, I don't think they are actually trying to make errors, but they feel the errors are inevitable and just need to be worked through. Kind of like ironing out the wrinkles in a shirt. I've tried ironing a shirt before, and let me tell you, that iron can nearly make those wrinkles a permanent feature. Those wrinkles don't go away just because you put an iron to them. It takes some technique to using the iron, otherwise you just end up with creases that look really really bad.
But if you want to work on your output, here are some ideas that I haven't tried myself.
Get a voice recorder and record everything that is said to you. That way you can write down what was said later. Eventually, you'll have a list of every possible question that people are going to ask you when you encounter a new person. Then prepare a response for each question. Don't wait for the whole list to be complete, of course. You've got to do your work as soon as you can. Once you have a response formulated on paper, get it checked by a native speaker. You can always submit this to a tutor at LingQ. Next, all you have to do is practice your response. You'll want to keep practicing it until it becomes memorized and flows fluently from your mouth. The first time you get to use it, you'll probably be all excited and even mess it up. But after a while, you'll be able to confidently deliver your answer. As a bonus, some of the questions in the list are ones you'll be able to use on others.
Another idea to make you effectively more fluent than you really are, is to practice short speeches of interest to you. Since you may find yourself using one of these, you'll want to use something that was actually spoken and not an article. By practice, again I mean memorizing. Eventually, the patterns of the sentences that you memorize will form reusable neural circuits in your brain that you'll have instant access to without ever needing to study the grammar (or actually, theory) behind them. You'll just know they say it this way because you remember it from one of your speeches.
That's probably about it for output. Pretty simple, huh? Just memorize a bunch of things you'll use and practice, practice, practice. If you're prepared, your language assessments will be sky high. With these ideas, just about anybody can look like he's fluent in three months.