Defense: how to avoid missed tackles

Question
Hello,
my name is Elimar and I'm Defensive Coordinator of Santos Tsunami, the Santos F.C. (Pel?s soccer team) Football team in Brazil. We are playing our first year at Brazilian League but we practice together as a team for about 2 years right now.
One thing I identify as the biggest problem of my defense are the missed tackles.
We do tackling drills, form tackle drills, ange tackle drills and more, the guys are working really hard and doing the drills 100% correct but when it comes to Scrimmage time they are all doing arm tackles, grabbing jerseys, sometimes it's almost like they are "hugging" the runner...we can bring the runner down but not immediatley after contact and everytime he can take 2-3 steps before falling and we keep losing too many yards because of that.
Do you have any tip, drill or anything that could help with that?
Thank you very much!

Answer
Hi Elimar, here are some tips on how to tackle.

http://www.youtube.com/watch?v=LvTROmHdMsw

http://www.youtube.com/watch?v=uZnRwBsOb5c&feature=relmfu

http://www.youtube.com/watch?v=SXtJB13goJg&feature=related

http://www.youtube.com/watch?v=VU6KeTmzya4&feature=relmfu

Good luck,
Louis