This is something I need to work on...
Seriously, stop stalling.
Do The Risky Stuff First
Have the hard conversations early in the week. Make the cold calls early (10 before 10?). Send that proposal on Monday. Put your neck out there as early as you can. That gives you as much time as possible to react and recover from how they turn out. It answers those lingering questions that are pulling on the back of your mind.
Best of all, it gives you instant feedback. The sooner you ask, the sooner you get an answer. The sooner you get things signed up or off your list.