1. Lo: look, consider.  in the orient: east.  gracious: benevolent, kingly.  light: i.e., the sun. —Throughout the poem, the progress of the sun from rising to setting is described metaphorically as the progress of a king from youth to age.

2. under eye: look, regard (of the king's subjects, or of creatures under the sun).

4. Serving: worshipping (as in the phrase "divine service").

5. steep-up: high and precipitous.

9. highmost pitch: apogee.  car: chariot (of the sun-god).

10. reeleth: falls away, staggers.

11. 'fore: before, previously.  converted: turned away.

12. tract: track, path.  look another way: i.e., look forward to the reign of the next king.

13. thyself outgoing in thy noon: passing the zenith of your beauty.

14. get: beget.