Jane Austen's art of characterization includes brief, often omitted, physical description; vocabulary; silence; tempo of talk; narrated dialogue; narratorial comment that touches on things like personality quirks such as sarcasm ("Is that his design in settling here?"), physical associations with things like aliments ("Ah! You don't know what I suffer!"), emotional denotations ("...cried his wife impatiently"); characters' attitudes, ideas, habits, feelings and mannerisms.
This art applies to Mr. Collins in a number of regards. First, since Jane Austen introduces him through a letter he has written, her first tool for characterization is vocabulary. You will find that Collins is full of fine phrases that themselves are excessively full of adjectives ("honoured father"), adverbs ("earnest endeavor") and elaborate nouns ("bounty and beneficence"). Austen next employs narratorial comment: "Elizabeth was chiefly struck with his extraordinary deference for Lady Catherine, and his kind intention of christening, marrying, and burying his parishioners whenever it were required."
In addition to narratorial comment, Austen also employs characters' comments on their own thoughts, feelings, attitudes: "He must be an oddity, I think,'' said [Elizabeth]. ``I cannot make him out." Austen also employs characters to comment on other characters' traits: [Mr. Benett] "There is a mixture of servility and self-importance in his letter." Austen also arranges for characters to comment on themselves through their behavior and habits: "Mr. Collins was punctual to his time,...He had not been long seated before he complimented Mrs. Bennet...he continued to apologise for about a quarter of an hour."
Austen's characterization of Mr. Gardiner employs narratorial comment (but not physical description): "Mr. Gardiner was a sensible, gentlemanlike man, greatly superior to his sister," "[Elizabeth] listened most attentively to all...and gloried in every expression, every sentence of her uncle, which marked his intelligence, his taste, or his good manners") and expression of his attitudes, habits, feelings and manners: Attitude: "Mr. Gardiner declared his willingness," "Mr. Gardiner, highly amused by the...family prejudice." Habit: "Mr. Gardiner, though seldom able to indulge the taste, was very fond of fishing." Feelings: "Mr. Gardiner expressed a wish of going round the whole Park, but feared it might be beyond a walk." Manners: "Mr. Gardiner, whose manners were easy and pleasant." this examination of Mr. Collins and Mr. Gardiner points out that a fine point of Jane Austen's art of characterization is that she spreads characterization out large extents of text. No part of characterization is laid out on a platter, so to speak, all at once, rather points of characterization are sprinkled hither, thither and yon.