Tired makes me worse as well. For example at the dentist, where I am extremely uncomfortable at to begin with. After being tortured\* in that chair for 30 minutes I am physically and mentally exhausted and can't speak for sh\*t. (\* It's a great clinic with very skilled dentists. It is just me who have a severe case of odontophobia) A trick I usually do for myself is to try to accept the fact that sometimes words do not play along at all. I try to let out a sigh, then force a smile and say something to the effect of "this is really not my day is it?" and a slight giggle. Sometimes that little gesture relaxes my audience. I've experienced that more often than not, they are uncomfortable when I stutter because I am visibly uncomfortable. Which can turn into a vicious circle of even more stuttering. By (at least trying to) appearing more relaxed about your speech, can often lead to your audience being more relaxed, which in turn makes you more confident and stutter less. Everyone is different of course so this is not a guaranteed effect, but it works for me (most of the times). (Did that wall of rambling make ANY sense?)