2. fickle glass: ever-changing hourglass.

3. by waning grown: grown more beautiful with the passage of time.

4. withering: fading, decaying. lit. and fig.

5. wrack: ruin; decay. i.e., Nature is mistress of decay because all living in Nature are born to die and death is the true beginning of wrack and ruin.

6. still: continually.

8. minutes kill: i.e., to render powerless the passage of minutes.

9. minion: darling; favorite.

10. still: always and forever.

11. audit: final accounting.   answer'd: settled; paid.

12. quietus: (1) a release or respite from life; an ending of life, death; something that causes death. (2) Means of settlement; discharge; quittance. (3) A thing that has a quietening or soothing effect; a salve, a sedative.   render: surrender.