If you have an accurate goto mount, you just tell it where to go, and start shooting. If not, then it gets rather time consuming as you point where you think the object is, take a long exposure and see if you got something. When I did M51 and M101 (see the "M51 at 400mm", and "M101 at 400mm" threads), I would do a 15 or 30 sec shot, and when I saw a faint smudge in the frame, I knew I was close. Then I took a few more shots to center the smudge, and then finally started my real data collection shots.
Then stacking all those frames turned the faint smudges into gorgeous galaxies.
Gripped 7D, gripped, full-spectrum modfied T1i (500D), SX50HS, A2E film body, Tamzooka (150-600), Tamron 90mm/2.8 VC (ver 2), Tamron 18-270 VC, Canon FD 100 f/4.0 macro, Canon 24-105 f/4L,Canon EF 200 f/2.8LII, Canon 85 f/1.8, Tamron Adaptall 2 90mmf/2.5 Macro, Tokina 11-16, Canon EX-430 flash, Vivitar DF-383 flash, Astro-Tech AT6RC and Celestron NexStar 102 GT telescopes, various other semi-crappy manual lenses and stuff.