What are some reasons Friar Lawrence is admirable in Romeo and Juliet?

Friar Lawrence is admirable because he does his best to help Romeo and Juliet and he has some very impressive skills. 

Friar Lawrence does seem to be the one person who really cares about Romeo and Juliet and the people of Verona. He is a good friend and advisor to Romeo. He does his best to make sure Romeo and Juliet can be together. He also has some skills with plants and potions. Despite the disastrous consequences, the sleeping potion he gave Juliet was clever and a good solution to a tricky problem. 

Friar Lawrence has the interest of all of Verona at heart.  When Romeo comes to him and tells him he has fallen in love with a Capulet, he sees it as a potential way to end the feud between the two families. He agrees to help Romeo with the hope that Romeo and Juliet's marriage would end the feud, saying,

O, she knew well
Thy love did read by rote and could not spell.
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' rancour to pure love (Act II, Scene 3).

Friar Lawrence again comes to the rescue when Romeo is banished. Romeo fought and killed Tybalt. Romeo should have been executed because of this, but Prince Escalus takes pity on him and banishes him instead. Friar Lawrence scolds Romeo for crying about this, and gives him a plan.  He tells him “the world is broad and wide” (Act III, Scene 3). Romeo is to go and wait; Juliet will soon join him.

After preventing Romeo from killing himself, Friar Lawrence has to deal with Juliet. She is upset because she is being forced to marry Paris, but she is already married. Friar Lawrence gives her the potion as a way to fake her death.

To-morrow night look that thou lie alone;
Let not thy nurse lie with thee in thy chamber:
Take thou this vial, being then in bed,
And this distilled liquor drink thou off;
When presently through all thy veins shall run
A cold and drowsy humour, for no pulse
Shall keep his native progress, but surcease (Act IV, Scene 1).

In the end, it did not turn out well for Romeo and Juliet, but it was not Friar Lawrence’s fault. His messenger did not get to Romeo because of a plague. Fate was against them. Friar Lawrence does admit what he did, though, and takes responsibility. In the end, he accomplishes his main goal: the families, united in grief, end the feud.