Personally, I take one day at a time. Slow and steady wins the race!
It also helps to set short term goals over the span of, say, a week vs. a month.
I'm about 15lbs into my diet right now and the only way I could've done it is with weekly goals (e.g. I'll lose 5lbs this week, and then set a goal next week based on my results). That way you break your entire goal up into segments.
That's the best advice I can offer. After that, seeing the results in the mirror is the best way to stay motivated.