You need look no further than scene one of act two to find Shakespeare raising suspense in his Julius Caesar.
Brutus broods over his decision to kill or not to kill Caesar. His imagery of Caesar as a snake makes his view of what Caesar might become concrete for the reader, and explains why the issue is vital for the future of Rome. This doesn't mean that Brutus is correct in his assessment of Caesar, but it explains how he feels. When Brutus decides to go along with the conspirators, suspense is heightened by his decision.
Intensification of the suspense occurs, then, when the majority of the conspirators arrive at Brutus's house and a deal or bargain or consensus is reached. Brutus by himself is one man deciding to commit an assassination; the conspirators together is a group of men deciding to commit an assassination.
Finally, the importance of Brutus, and therefore the importance of his decision to join the conspirators, is revealed when Caius Ligarius ignores his illness and follows Brutus. Brutus is shown great respect and honor in the play, which makes his choices vitally significant.
The suspense, then, builds as Brutus decides, the conspirators agree, and the status of Brutus is enhanced.