The most common modulation is to the dominant. Have a look at several sonatinas and you'll see how it's managed by quite a few composers.

The 1/2 step modulation bnich mentioned is commonly used in popular/contemporary church music. It's basically a common-tone modulation: the tonic becomes the third of the bVI, which then becomes V in the new key. You can do the same with other notes. For example, if you take the fifth of a chord and treat it the same way:

F (I chord)
Ab7 (the C in the F chord becomes the 3rd of this chord, which is V7 in Db Major)
"If we continually try to force a child to do what he is afraid to do, he will become more timid, and will use his brains and energy, not to explore the unknown, but to find ways to avoid the pressures we put on him." (John Holt)