Excellent game. I recommend getting comfortable with the base game before adding in expansions. They increase the challenge (as well as the fun) so it's a good thing to be familiar with how to work the base game first.

As for strategy, the most general suggestions I can make are to make sure you are making good use of your time with each board. I don't want to say too much because a big part of the fun of the base game is in solving how to beat the system. Make sure you understand the full use of putting on the Ring - it's essential to make it through rough spots and its ability to interrupt the action is central to that end.

Once you've beaten it once on 15 set Sauron on 12. The game offers a consistently good challenge but is very beatable on 12 once you are familiar with the different aspects of the journey. I'm at the point now where, in the base game by itself, only the worst luck will cost the Fellowship victory with Sauron starting on 12. Starting him on 10 is a different story....

Also know that the game plays differently with different numbers of players. Looking at the two extremes, a two player game will have an easy time avoiding corruption from missing Life Tokens and will have Gandalf available early and often thanks to the shield points being concentrated between the two of them...but hobbit cards will be at a premium and being able to manage them is no small task.

With five players you should have plenty of raw resources to get through the boards but corruption is GOING to occur...there simply aren't enough Life Tokens to go around. Additionally, Gandalf will be available less frequently. More players requires more forward planning on who is going to take what to ensure that the group as a whole sees the most benefit. Three and four player games scale between the extremes accordingly. Have a great time.