You don't necessarily need to completely customize everything... In many cases, however it's more important to have good structure and information.
Start off with a basic introduction paragraph or two of what type(s) of positions you are looking for. Followed by a brief summary of the keywords related to the technologies you've used, or are experienced with. Follow this by either eductaion or work history next, whichever is more recent/relevant (if you're still in school, or haven't had a job out of school, education first)... Point out each role, accomplishment and related technology used.
In work history, give a brief paragraph for any major roles/projects again, with any related technologies used. Also include aliases and related technologies.
By doing this, you give up front what you're looking for... what you can use, and then back it up again. Have others who are great with your language proof read and give feedback on verbiage.
Half the battle is getting through the H.R. and recruiter types that hold the gates to the decision makers. The other half is following through with actual relatable experience that you understand, know or can easily learn what you need for the job in question.
Be honest to a fault in terms of what you know, what you don't and what you feel you can learn quickly.
That's my advice to anyone looking for a job in a technical field... You don't necessarily need to customize, but at least have a great resume, that will go a long way getting your foot in the door.