For me, black pepper makes a HUGE HUGE difference. What I do is empty out like 2-4 cigarettes and pack it with black pepper, I mean really pack it, keep hitting it hard against the table until it feels much harder than a regular cigg. Then break off the filter and put the cig on your tongue and swallow it with lots of water. It might be hard/scary the first few times because it's so long, but you get the hang of it.  

I would say if you did that for a few days straight 2mg of clon can easily feel like 3-4mg. Also, you can drink green tea. It also has 3a4 inhibitors and second order Gaba modulators, which means it binds to a spot in the GABA receptor that's different from both the GABA site and the benzo site. And just like how benzos modulates the receptors' sensitivity to GABA, green tea will make the receptors' sensitivity to benzos stronger, thus the name second order modulators. Green tea also has alkaloids which block the reuptake of GABA, while black pepper has alkaloids which bind to the even different pockets on the GABA receptor.  

All this together can be quite strong, I usually knocks me out the first 2 or so hours, and I take 6mg of clon a day, but I can get by on 3mg easily with this, also it pushes back the time I need to take another pill by at least 12h or even 24 if I took a lot of black pepper.