Job searching can be so frustrating.  Fortunately I haven't had to do it in a while, but I do conduct interviews.
I agree with Crankin that you should always look good, even if you are just picking up an application.  That doesn't mean you should wear a suit, but unless you are applying to a bike shop, don't wear a jersey.  I also agree to check with the job placement offices at school.  Also let your professors know that you are searching.  When we open a new candidate search, the first person I call is my graduate advisor.
Think about the challenges you faced in the temp jobs or volunteering.  Did you have to work with a lot of people and personalities?  Handle high-pressure situations?  Learn new skills quickly?  Operate on a shoestring budget?  Organize other volunteers?  Parley these into skills on your resume.
When they ask if you know how to make coffee or fix a bike, don't tell them what you don't know; tell them what you do know.  "I do small repairs on my bike, but have limited tools...  I am very mechanical and learn quickly...  I help my friends do simple repairs on their bikes..."
Also, when you apply on-line, notice the key words in the ad and tailor your resume to include those words.  Whether it is scanned by a computer or a person, those words will be picked up on.  Just don't turn your resume into a stream of jargon.  And do NOT use the same resume for every job.
Good luck.
				
			 
			
		 
			
				
			
			
				I stand and rejoice every time I see a woman ride by on a wheel...the picture of free, untrammelled womanhood--Susan B. Anthony