Here are some such features as you can build your answer upon:
1. The poem opens rather suddenly with a a typical Metaphysical shudder;
2. Donne employs a rather argumentative design as the lover addresses the beloved;
3. The title Good Morrow itself is a typical Metaphysical conceit and you will find such other condensed metaphors in the poem, e.g. the eyes of the lovers being called better hemispheres;
4. There are scholarly allusions/references, such as that of 'the seven sleepers' den and the theory of pure substance;
5. The poem moves from a past world of body to a present world of mind and thence to a future world of spirit'
6. The poem is strikingly dramatic and witty;
7. The poem initiates with a number of crucial questions, interrogation being the staple of Metaphysical search;
8. Unlike the Petrarchan convention, the poem celebrates the joy of mutual love.