For therapeutic use, take it as directed. If your doctor didn't make this clear, you should take it on days when you do need to focus - so probably not taking it on weekends, for example - in order to reduce tolerance buildup.
For recreational use, break the time release (crush it to dust) and eat it, or if you must, snort it (snorting adderall, particularly the XR, is not recommended unless your tolerance is really low and hence you're taking small amounts of it, the pills contain too much inert crap that just clogs up your nose, and blocks the inevitable redose from getting to where you want it); be aware that abusing adderall will raise your tolerance and make it less effective for therapeutic use, and you shouldn't abuse it if you have ADD and need it to be effective at work/school.
Everyone I know, including myself, who has tried to abuse the XR has found it to qualitatively worse (with a less favorable physical-crap-to-mental-high ratio) than an equivilent dose of the instant release adderall, despite the fact this makes no sense from a logical perspective (as the active constituents are the same and present in the same ratio) - yet it's observed consistently enough that I can't ignore it. I find the XR to be useless for recreation, while I do enjoy instant release adderall (not enough to make it worth the comedown, but at least there's recreational value there, while I can't say the same of the XR)