Just use Google or DIYMobileAudio to get the details, but basically:
1. Use a powerful amp. (you might stress your battery or alternator, but hey, it's a small price to pay for being heard from three blocks away). Take note many cheap-***** amps are lying through their teeth about power ratings, like those rip-off Alpine V12 amps sold for cheap with a huge "1200watts" sticker on them.
2. Design a good box. Ported box can get louder, but do it wrong and you can damage the sub. Do any box wrong, and the box can explode. No kidding, JLAudio warns against using a large box with no internal brace somewhere on the website (can't find it now though); what you can do is build a large box (to specs of course) but leave panels to brace the box every 12" or so, but drill a hole in it the size of the sub (only so it'll be easy since you only use one circle template). Make sure to take into account the effect on the volume - get the volume of the brace prior to the hole then subtract the volume of the solid circle you cut out to get how much what wood is left takes from the internal volume.
3. Use a receiver with a proper preamp output to the amplifier and level-match properly.
4. Use Dynamat or a similar product where it will matter - like behind the rear license plate and at least all over the trunk lid. You do not want clunky resonance from the pounding on the car body making sure your car sounds/looks cooler from outside than from inside.
5. Use the right music - Li'l John works great for pissing off neighbors and other motorists. And according to my friend who stuffed his trunk with two JLAudio 12w6 V1's, powered by a 1,000w JL mono amp, music from a Pioneer touchscreen and still using the crap paper cone speakers in the doors who was amazed I upgraded everything inside the cabin and zero subs : "When people start cussing at you or cops pull you over, that's when you know you did a good job."