As a manager, I often have to take a lot of time to fire someone. Mind you, I work hard at not having to because it hurts, but when I have to, it takes a lot of time. Here are your signs. By the way, if you're worried about getting fired, I suggest two steps: see a therapist to find out if you're just paranoid, and then get out your resume. If you're that miserable at work, then you need to move on - unless you move on a lot, and then it's therapy time.
1. You no longer get good assignments. If you request projects and are turned down for most of them, then you have a problem. You have been cut out of the premium assignment queue. This is not good. Work diligently at the assignments that you do have and put your name all over them to see if you can get the premo ones again.
2. Your boss asks you to document your work, your time, or your productivity. If your boss is doing this, then she is documenting you. If you get a new boss (and I am frequently a new boss), check to see if she's asking everyone for this information to reduce your paranoia. If it's just you, then you have a problem. Document honestly and then improve your performance in whatever you're being asked to track.
3. Your boss asks you to cross train someone. In the old days, we often refused to do this as it made us replaceable. Now, we must because we have to show team spirit. But if you are suddenly asked to give up something to someone else, then your job is changing.
4. Your boss ignores you suddenly. This needs to be a change in behavior, but if your boss stops talking to you, then he is assuming that you're already gone or working on not letting you know that he is documenting you.
5. You've had more than one chat about improving something. It is awful to have to sit an employee down and tell him to improve something. I hate it worse than dental work. If your boss is forced to sit you down and do some coaching - especially outside of the performance review period - then you are in trouble. Don't ignore this signal as it being his problem: coaching is the first step to firing. The steps are: coaching, performance improvement plan, then the warnings. Once you get to the warnings, Human Resources is in on it and it's hard to go back.
6. Human Resources has been involved with you somehow. If you have had a chat that you didn't ask for with an HR rep, then they are involved in your job status. That is a bad, bad thing.
7. Your boss refuses to meet with you unless there is a witness. I've never done this, but it's a sure sign that you are being documented and that your employer is protecting itself.
8. You find yourself with nothing to do and your colleagues are busy. This is also a sign that your work has been reassigned to people who get to stay. Ask for an assignment then, do it really well, and be at work a lot.
9. You are no longer allowed to go to meetings, and your requests for conference travel is refused. Pay attention, though. If that is happening to everyone, then it's just a budget thing.
10. Your boss sends you ads. I've actually done this, but with an employee who announced that she couldn't stand me and was leaving.