How to finish knitting a sweater, this can be an elusive task especially a full sized knitting project. Is there an unfinished project like this is your collection of works. Maybe it is done up to the complicated bits or all in pieces that need to be sewn together.
The trick to finishing a larger fiber project is never put it away. Work on it every day, every other day or worst case once a week. Keep track of where you are at in the pattern and if you need to add other small projects that's fine, but once you put down a sweater you may lose your place and if this is a new skill it can be difficult to rediscover where to start up again.
Sometimes picking up a project that fell by the wayside is intimidating because you likely put it down at a complicated place, therefore, always forge ahead even at the tough spots. If you are still in love with the yarn and the idea of the sweater but don't know how to start from where you left off march down to your favorite yarn shop and ask for help or bring the piece to your knitting group and ask someone. Another problem that can happen is sewing all of the pieces together, if this is a hurdle that you just cannot overcome, pay someone to finish it up.
Of course if the whole thing has become too daunting, frog it and make mittens, a scarf and matching hat knowing in the back of your mind that next time you will finish that complex sweater.