One of the more underused but useful tactics for entry is the "false strike." A false strike is a full strike not intended to actually connect, but close enough to draw a response. Note that the difference from a fake is that a fake/feint is usually a body indication of a strike that doesn't really get thrown. The advantage of a false strike is that it can be more convincing than a fake, but if the opponent tries to time-hit (strike at you as you are striking at him), then you should be just out of his range, and if he responds with a simple hand defense without moving out of range, then you are that much closer to changing up your strike or jamming up his hands.
To play with this, A throws a false jab or cross at B, and B throws a looping right or left (to use common punches) which should not be close enough to connect if A is controlling his range, OR tries to block A's strike. A responds to the attempted counter-strike by following in with a real strike, and responds to the attempted block with either another strike or a trap.
As with any drill, work at a speed that helps both partners.