When you want to watch a movie there are 3 big steps you must do before you actually waste your time:
1. Watch the TRAILER : When you watch the trailer and actually find it really interesting to see the movie the you must do it. But if it doesn't really pull you in then you must not see the movie or you can move on to step 2.
2. Check the ACTORS and PLOT : Usually good actors play in good movies, but there are hundreds of times/movies where a good actor/actress play in really rubbish movies. Also by reading a small summary of the plot is really good in getting a feeling what's the movie about.. A really good or the "top" website about this is: http://www.imdb.com/
3. Check the BACKGROUND : Really important. You might say why I need to do it? Why take the trouble? Well, the answer is simple because you don't want to wait 1,2, 3.... years until you get at the end of the story. Usually when a new movie get out they are not going to tell you that is a sequence of 2,3,4 etc parts until you get at the end of it... When you do the background research you will know if the movie comes from a book, which is the most common for sequence movies or the producer future plans.
That had happened to me twice, when I didn't do enough research...saw a nice trailer and went to watch the movie.. at the end they cut you in the middle and you are going...WHAT???.. after that you have to wait 2 years to see the continuation. To give you my example when it first happened it was with the movie "Golden Compass"... I saw the trailer and though seems like a good movie lets watch it... at the end is cutting right in the middle of the story and let you hung there... I researched to find the next part or some information about it... and what you know there's not going to be any because they didn't sold as much as they wanted to.
I don't warranty you will get a great movie if you follow the steps but you will certainly avoid disappointment for waiting parts and get a feeling of the movie quality.