Don't put your foot in between the suspect's feet. He can drop and twist his legs against one of your legs to lock you up and take you down. Once you begin moving a suspect into a position to handcuff him, keep him moving so he's off balance, even if you must change the direction you're moving him. The idea is that he's continually trying to catch up to you, but he can't if you quickly get him into handcuffs.
Collars — Step to the side of the suspect as you grab his collar and wrist (two points of contact for better leverage and so he can't slip out of his shirt or jacket) and yank him downward. Then bring his wrist up behind him and command him to put his other hand behind him to put handcuffs on him. In some cases, for example if he's tall, you may want him to go to his knees. To achieve this stomp your foot on the back of his knee. Then cuff him.
Another way to use the collar is to reach from the front and grab the back of his collar and pull him downward to handcuff him.
Belts — Have the suspect turn around and put his hands on his head. Then step forward and grab his belt or waistline and the back of his collar. Press him into a wall or vehicle then order him to put his hands behind him to cuff him.
If there's no wall or vehicle, push forward on his waistline at the same time you yank downward on the back of his collar to make him go to his knees to be handcuffed. (If you step on the back of one of his knees, it will make it easier for him to go down to his knees.)