one tactic is to try and keep any important piece of theirs in front of their king and try a fork or a pin... its a really irritating tactic to them and you might see a lot of wins through resignation...
atleast ive seen that 
Bullet chess tactics
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Jun 4, 2010
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#4
Schachgeek wrote:
Towards the end of the time control one tactic (that I am beginning to adopt) I see lots of players sacrifice pieces with check, or just plain make pointless checks.
Remember if you're in check, you have to get out of check and this invalidates your plan or any premove you had set up unless that premove is a legal move. (escaping from check).
Forces you to think again while your clock ticks away.
What's fun with this approach is that you get the sauciest swear words from a stronger opponent who loses to your 0.03 seconds clock balance.
Who says you can't make friends with chess? :)
In bullet chess, the main thing is to keep your cool...
I've learnt that chaos due to loss of time is the main cause of losing bullet chess matches. It's Interesting that to most people, the tactic would be:
"OK... I just need to play any random move and eventually it turns out to be a good move"
This however is not the case. The golden rule is mentioned in gold above. Here is a match to represent an example. I had only about 14 seconds left and my opponent had around 16. It was a rush-hour experience in the endgame.