There could be many explanations for the things you've mentioned. For example, in the tournament scenario, it could be that you're being a little too over zealous trying to take advantage of everyone tightening up near the bubble and you're getting married to much lesser quality hands. Then again that might not even be close.
But there is definitely some help available from the lot here. Sounds like you've done a fair bit of reading. For tournament play, go back to HoH again and reread. Otherwise, as far as this site is concerned, my big suggestions for you are...
1. Read the Online Poker Guide
2. Read most everything in the Articles Section (http://www.cardschat.com/poker-strategy.php).
3. Begin posting some in the Hand Analysis section. Focus on the hands that are getting you in trouble. Oh, and check out the posting rules in that section so that you get the best feedback from people. One big hint is to leave off the results and cut your hand history off where you have your first difficult decision and go from there. That could be PF or facing an AI river bet, doesn't matter. Just leave off the results initially to get non-results oriented feedback.
Start with those.