So, you've been training for a while and just don't seem to be making much progress anymore.
Some people train steadily with minimal results and others make great progress.
After a few months of training your body gets used to it, especially if you continue to use the same weight and the same routine. When you see your gains start to slow down, that's the time to look for new ways to increase intensity. There are several ways to do this, most of which are listed below. Which ever you choose, use it 1 to 2 times a week for a few weeks, then try another one. You can still do lighter weights for higher reps, but make at least one set a heavier one.