I'd like to zero in on the affection, devotion, and loyalty that is revealed between Elinor and Marianne, in spite of their different temperaments and personalities. Miss Austen compares and contrasts the two sisters in a variety of situations throughout the novel. One of my favorite examples (apologies for the long quote) from Ch 34:

"........Marianne could not bear this. She was already greatly displeased with Mrs. Ferrars; and such ill-timed praise of another, at Elinor's expense, though she had not any notion of what was principally meant by it, provoked her immediately to say with warmth,

"This is admiration of a very particular kind! -- what is Miss Morton to us? Who knows or who cares for her? It is Elinor of whom we think and speak."

And so saying, she took the screens out of her sister-in-law's hands to admire them herself as they ought to be admired.

Mrs. Ferrars looked exceedingly angry, and drawing herself up more stiffly than ever, pronounced in retort this bitter [philippic]: "Miss Morton is Lord Morton's daughter."

Fanny looked very angry too, and her husband was all in a fright at his sister's audacity. Elinor was much more hurt by Marianne's warmth, than she had been by what produced it; but Colonel Brandon's eyes, as they were fixed on Marianne, declared that he noticed only what was amiable in it; the affectionate heart which could not bear to see a sister slighted in the smallest point.

Marianne's feelings did not stop here. The cold insolence of Mrs. Ferrars's general behaviour to her sister, seemed, to her, to foretel such difficulties and distresses to Elinor, as her own wounded heart taught her to think of with horror; and urged by a strong impulse of affectionate sensibility, she moved, after a moment, to her sister's chair, and putting one arm round her neck, and one cheek close to hers, said in a low, but eager voice:

"Dear, dear Elinor, don't mind them. Don't let them make you unhappy................."

I love Marianne's impulsive and courageous public rebuke of Mrs. Ferrars....something tactful and cautious Elinor would NEVER attempt! So, we get the two sisters alternately being puzzled by, then admiring the qualities and strengths in the other that they do not possess themselves. Thus I get a slight grasp on the title "Sense and Sensibility."