Liberally abuse drugs, especially if you can get your hands on a hypospray. As I understand it chems trigger their addiction probability when first introduced into the body, and the hypospray just fucking skips addiction chance, meaning you can amp yourself up with a "lighter" drug like meth/nicotine/etc. very rapidly (and in configurable amounts, if you're using the hypospray) when needed. Great for managing stuns, running away from an unwinnable situation, muscling past breaches, and so on. Meth can be found in certain sodas (robust-eez I think), and if you REALLY can't find a hypospray (there's roughly 7 in medbay in various places), there are some in the debris field.
Not quite a combat tip, but there's an easy way to manufacture hobo charcoal: burn paper to make it into ash, then scoop up the ashes in a container. Add salt from the bar and heat with a welder. After a certain heat it will turn into charcoal (374 K if I recall) and can cure your woes without stumbling all the way to Medbay.
Hide behind shrubs when you're off-screen from someone chasing you.* Unless you have giant obnoxious clothing, 9 times out of 10 they WILL NOT notice your few pixels around the shrub and will just keep running after you, usually not realizing their mistake until they're several sectors away from you.** Great for evading a rampager or wizard or something.
Trade with the Clown for his PDA, or steal it off his dead body. It's good for slipping people without having to find/use chems/a mop.
(*This may not work if your pursuer is fast enough to catch up to you, this is assuming you're both at standard speeds.)
(**Unless they read this tip.)
EDIT:
http://wiki.ss13.co/Guide_to_Being_Robust