Typically I align the hole in the tuner so its basicall perpendicular the the nut.
Then I put the string thru and pull till no slack, then I put my fingers about 2 1/2" up the string and push it back to the tuner.
Begin to tighten the tuner. For guitars having three tuners on each side, always make sure you tighten so the string comes down in the inside. For six on a side (non reversed headstock) the string should be on the underside of the tuner. For six on a side reverse headstock they should be on top of the tuner.
Now, as you tighten the first wrap of the loose end should go above the string, the remaining wraps (~3) should go below. Many people reverse this but the main thing is to do the first wrap on way and the remaining on the other side. What this does is to pinch the string allowing for more consistant tuning. Hope that helps