I know that it comes with practice, but what exactly should you be concentrating on when practicing them to make your punches, etc. intense/sharp? For example, when I'm doing a high block, I turn my fist outwards at the last moment like I'm told to, but it still looks incredibly weak and lame. Same with a sudo block. On the other hand, I've seen 10 year old greenbelts somehow perform these blocks like they have been doing it for years.