I'd probably put them up on Ebay and buy a pair that fit right. About
the only things you
can do with these are to wear a heavier sock or to put in thicker foot
beds. Both of those
will help, but how much is a question, don't expect them to ever be
right. Plus as they pack
in over time, they will only get worse.

When trying on a boot and wearing them use a thin sock. Later, if you
need to, you can go
to a heavier one if you really need to.