What are some decisions that Friar Laurence makes in Shakespeare's Romeo and Juliet?

Friar Laurence makes two of the most important decisions in Shakespeare's Romeo and Juliet. First, he fatefully decides that it might prove beneficial to everyone involved if he married Romeo and Juliet. In Act II, Scene 3 Romeo, who has just left Juliet after professing his love for the girl, goes to the Friar requesting that the Friar marry them. The Friar is initially taken aback as just the day before, Romeo was in love with another woman. After chiding Romeo about his promiscuity, he comes to the conclusion that this is just what is needed to end the bitter feud between the Montagues and Capulets. He tells Romeo,

But come, young waverer, come, go with me.
In one respect I’ll thy assistant be,
For this alliance may so happy prove
To turn your households’ rancor to pure love.

The second important decision comes when he devises the plot for Juliet to fake her death. Juliet is desperately searching for a way out of the arranged marriage to Count Paris and, after seeking advice from the Nurse who lets her down, comes to Friar Laurence's cell. She suggests that she would rather die than go through with the marriage and is carrying a dagger, presumably to kill herself with. After hearing of Juliet's resolve to avoid marrying Paris, the Friar comes up with what he feels is the perfect solution. The audience knows from earlier in the play that he is somewhat of a chemist, so it comes as no surprise that he would be able to concoct a potion which would render Juliet in a deathlike state. He says,

Take thou this vial, being then in bed,
And this distilling liquor drink thou off;
When presently through all thy veins shall run
A cold and drowsy humor; for no pulse
Shall keep his native progress, but surcease.
No warmth, no breath shall testify thou livest.

He also plans to send a message to Romeo in Mantua informing him of this plan and urging him to come to Capulet's tomb to retrieve Juliet so they may once again be together. Unfortunately, miscommunications and simple bad luck thwart the Friar's plan as Romeo never receives the message and ultimately poisons himself in the tomb next to the sleeping Juliet. When she awakens, she too claims her life as she stabs herself with Romeo's dagger.