Well I have many tricks but they are still "secrets" but the best thing I can recommend is try to degrease the worm gear (level wind) and remove the spool and clean the spool shaft off with a q-tip and rubbing alcohol. Also clean the raceways on the frame where the spool rides and the outside edges of the spool. This should help the freespool out, also when you get the excess grease off of the worm replace it with the oil that is supplied with the reel. Anything else and you would have to send it in to Shimano and have that guy trick it out.

I hope this helps!