some of my suggestions have been mentioned already but are worth stating again:
do your deadlifts with an overhand grip
do deadlift holds inside a rack, til failure
do reverse barbell curls and wrist curls with a towel wrapped around the bar (or sponges), making for a thicker bar and to provide some grip resistance
do wrist curls with the bar going down to your fingertips
take advantage of the various other methods out there, dyna-flex gyro ball, gripmaster, wrist roller, grippers, even squeezing a tennis or racquetball works
and yeah, STOP USING STRAPS