Taking the waist in on jeans is about the worst job ever.  Place darts on the back of the waistband between the belt loops.  You can also make a tuck at the side seam on one or the other side of the belt loop.  You'll likely have to do both of these things to get them to fit because you can't take up too much in one place. This is the easier way.  Oh and be careful not to sew the pockets into your doin's.

You can always take off the waistband, take them in, put the waistband back on.  I don't recommend this in store bought pants because you never know what you are looking at.  There could be 1/4-inch seams, the zipper might not be long enough at the top to catch it back in when you put the waistband on (I have also lost the tab off the top of zippers and ruined the jeans). 

You can do it either way.  If I try to buy jeans I have to get about 4 inches out of the waist by the time they fit the rest of me.  So, I make my jeans.  It is not difficult, I used to make a lot of them for my girls too.  I used a denim sewing machine needle, which you might want for the alteration.  They are made by Schmetz and say "Jean" or "denim" needle on the package.  They have a different shape to the shaft and are not cylindrical.