"I wish I could just tone up this (insert body part here)"
To tone a specific body part it takes two phases, the first is a build up of muscle tissue. This requires progressive overload weight training with a consistent base of strength. It also requires a slight calories SURPLUS, meaning that you are eating more calories than you are burning.
Yes, some fat gain while occur while being in a surplus. It is a fact, the body can not designate all of the added calories to muscle building. However it is a small sacrifice to add some fat due to the fact that you are building new muscle tissue and building the areas that areas that you want to tone.
The second step after you have been in a surplus for a number of months is that you need to start a cutting or diet phase. The key is not to back off of your strength training while you are cutting because you do not want to lose the new lean body mass that you have built up. Training should remain the exact same regardless if you are cutting or gaining. During this cut when you are shredding fat you start to reveal all of the hard work and muscle tissue that you have built up during your calorie surplus phase. All of a sudden you have toned muscle definition that looks amazing.
The key is to remember that every toned look started with a bulk.