I am trying to finish up the top of my wet bar with stain and polyurethane. All finished with the staining and have applied 6 coats of the poly. Are there any tricks techniques to get that final smooth brushless finish?

Well normally to get that kind of smooth finish you have to sand with steel wool between coats and clean it with a tack cloth each time.

I do sand between coats with a very fine grit sand paper (around 400) and then clean with a cloth before applying the next coat.

Well depending on the type of poly and if its not coming out glossy try using a high gloss varnish on top. Just make sure the product your using can take varnish