Nothing tunes a reader out quicker than a main character who achieves his goals too easily. It's like being in class with the annoying brainy kid who gets an A on every assignment and doesn't even break a sweat. Real people have challenges. Their lives aren't easy. Ironically, when we read to escape our own problems, we want to immerse ourselves in the setbacks of a frustrated protagonist.
Tension Technique #4 -- frustrating your protagonist -- is all about making it as difficult as possible for your character to accomplish his goals. Give anything to him too easily and you've thrown aside what should be one of the most often used tools from your author arsenal.
If Reggie needs to win the Battle of the Bands (goal) to get the attention of his secret crush (motive), a few obstacles thrown in his path will not only build sympathy but heighten tension as well. Maybe Reggie's old electric guitar gets stepped on three days before the competition. Reggie searches pawn shops and garage sales for two days; but, when he finally finds a replacement, his jealous rival, accompanied by a gang of cronies, chases him down an alley and steals the guitar. By a miracle, Reggie manages to acquire a third guitar. Blow an amp and break a few strings two minutes before his band goes on stage and you've really cranked up the tension. The very things that make life more difficult for Reggie is what makes readers root for the hero and turn pages.
To introduce this technique, I sometimes give students an unsolvable crossword puzzle. Every time they think they've found an answer, they discover it won't fit. You don't want to let this activity drag on too long, but a few minutes of frustration and an example or two from a popular novel help get the point across.