Developing explosive speed can be achieved by doing specific plyometric drills and resistance training...ie: cord drills. Since you have already included plyometric drills in your work out, begin to utilize resistance training. The plyo's you mentioned are very basic there are many, many more. Check out:
www.progessionsports.com
Plyometrics should not be done everyday. Try a program including plyo's 3 days a week with a resting phase day in between. Alternate plyo's with resistance training.
Be very careful that you are doing the plyo's correctly they are very hard on hamstrings, quads and the knee joint. Good luck
