Just kidding, but in the future, add some more context...
I'm assuming you are talking about process capability, in which case this has to do with how well a process can perform the function within your design specifications. There are many ways to increase the number, but not all of them are practical or cheap. Sometimes it's a simple matter of replacing a piece of equipment which has the lowest precision, it's also possible to go the other way and reduce the precision requirement of the process (say from 6 sigma to 4 sigma) though places don't generally do this if possible, as this can lead to quality issues.
I'm pretty sure that .08 is a dreadful index, pretty much saying that your process is not adequate for the desired production specifications...anyway,check wiki first in future http://en.wikipedia.org/wiki/Process_capability_index
This site goes into some nice detail on it in layman's terms:
http://www.isixsigma.com/tools-templates/capability-indices-process-capability/process-capability-cp-cpk-and-process-performance-pp-ppk-what-difference/