There are aspects of martial arts and grappling that sometimes don't get the attention they deserve. For one, the importance of solo training. Now this may be a rather broad topic, and it is, but if you boil it down it's basically all the training you can do off the mats. I know throughout my grappling career this has been the most important training method I could have employed. There have been many times over the years were I can't make it to practice, I was hurt or didn't have an instructor or training partners. What I did to keep myself sharp was not only work on drills and mechanics related to grappling, but I also spent a great deal of time visualizing, analyzing, watching videos and reading. What's great about solo training is that not only can you supplement your regular mat time with it, but you can implement a training regimen when life or injuries keep you from stepping on the mat.
Now, the only true way to get better at something is to do that something over and over. If you want a better headlock or guillotine, work just that - much like Marcelo has for years. Lifting weights, doing Crossfit or Prancercise may be great cross training additions, but they don't help you get better. Take it from today's video where Mark Hatmaker demonstrates a solo drill to strengthen your front headlock (guillotine/chancery/front choke/grovit etc.)