Couple things to consider.
1 - ET is made in the first 1/8th mile.
2 - Speed is made in the last 1/8th mile.
So, to lower your ET, the best way is to have a better 60' time.
As Moparleo questioned, how old/tired is the motor? Before you make horsepower increases or gearing changes, can the motor stand up to the higher rev's or pressures from higher HP? Same question for the rest of the drive train.
If a compression check shows the motor is worthy, my opinion is to install a progressive controlled nitrous unit. You do not need a BIG unit to do this, a 150 HP unit should suffice, but talk to a NoS supplier and they will tell you what size. Remember, just because it's there doesn't mean you NEED or WANT to use ALL of it! The progressive controller can allow you to bring in the horsepower gradually and not shock/smoke the stock tires. Slicks would help, but not necessary. You just experiment with the controller on how much and how fast you bring the juice on. If your looking for a stock engine look, hide the lines above the tranny and enter the from the back of the block and run the lines to the intake ports under the intake manifold. This costs a lot more than the carb plate style, but it you want the bone stock look, that's the MOST COST EFFECTIVE way to drop your ET substantially and STILL keep it a daily driver and not do any other major modifications. This way you only use the horsepower when you need/want it and the drive train lasts a lot longer. The other trick I will share is to use the floor mounted windshield washer switch to activate the NoS as you probably don't spray the windshield anyway. NO ONE will ever figure out how you activate the unit!
A little nitrous is good, a lot of nitrous is great, too much is really, really bad....... don't get greedy!
