Yeah as was already said, sounds like you're using builds you're not familiar with and applying runes and insignias which aren't suitable.
The game isn't so easy that you can load 8 skills on your bar, and 8 on each of your heroes, it takes a little bit of thought. GW and similar games are not merely about pointing, clicking and winning.
Now I would suggest letting us know what heroes/henches you are using for these sections of the game as I have builds that can walk each of these no worries, as I'm sure others have.
Try changing your tactics frequently, you need to know what works in different places, for instance sometimes holy damage will work, sometimes fire, sometimes a mesmer with a particular build won't be a good option.
You may also like to try wiki.guildwars.com,
http://guildwars.wikia.com/wiki/Main_Page and
www.pvxwiki.com for some help if you can't figure it out, ask someone but these are some of the best resources.
Also try searching the forums here because some folks on here know far better ways of doing these things than I do, and I can walk the sections you're having trouble with. Good luck, see you in game.