I would like to infuse alcohol (gin specifically) with basil, but basil is quite a fragile plant and doesn't seem to react well to sitting in booze for a few days. I tried muddling basil and putting it in an air tight container with my gin. I stored it at room temperature in a dark cabinet and tasted it daily. After one day it was starting to get a hint of basil, but the taste was not strong enough. The color was a pleasant light green. After two days, the color had gone greenish brown and the flavor had gone south. It's hard to explain, but it was not good. I assume you'd have the same issues with mint, parsley, cilantro, etc.  How can I get a better basil flavor in my infusion? Should I just use a ton of basil and infuse for a day? Should I not muddle the basil? Should I blanch the basil? 
If you have access to an iSi or other whipped cream charger, you can use it to infuse very quickly, eliminating any off-colours or off-flavours that would develop from steeping. There are several posts on this process, including one at Cooking Issues and another at Playing with Fire and Water.  It's really very simple, just add your flavouring agents to room-temperature liquid, charge up, swirl for 30 seconds, let stand for 30 seconds, vent and strain.  The working theory seems to be that the high pressure forces tiny bubbles into the flavouring items, which then escape back into the liquid after releasing the pressure. Whatever the scientific explanation is, it works brilliantly.  Don't crush or muddle them first. That leads to rapid enzymatic browning, even when preserved in alcohol. 