Focus
 

Keep your focus on the muscle you're training

>> British researchers discovered that subjects who focused on their biceps while doing biceps curls had significantly more muscle activity than those who thought about other things. More muscle recruitment can result in more muscle growth in the long run. Be sure that for every rep of every set during your workout you're thinking about the muscle(s) being trained, instead of wondering where that blonde wearing the short shorts went to do her bent-over rows.