The first time Serena Joy is introduced is when the Handmaid talks about how she tends to see her in the garden. "Sometimes the commanders wife has a chair brought out, and just sits in it, in her garden." This makes her sound quite lonely as she enjoys passing time admiring her garden, it can also imply how she is quite proud as it is described to be something she cares for. The personal pronoun 'Her' suggests how she owns and cares for this garden and could also suggest a sense of possessiveness as it belongs to her and she likes to be in its surroundings showing her ownership. We also learn how she is a Seamstress, as well as a gardener which could suggest how she has some free time and could possibly be quite old as these are activities mainly acted by elder women. I aslo noticed how these are typical female domestics.
Another perception i gained from Serena is that she can be quite Intimidating "I dont like to come upon the commanders wife unexpectedly" , this shows how the Handmaid is in discomfort when in presence of Serena, this opinion implicates her intimidating and inconsiderate nature.
This also ties into how she welcomed her into the house when the Handmaid first arrived.
"She just stood in the doorway, blocking the entrance" The noun 'blocking' suggests how the wife purposely intended to make the Handmaid feel uncomfortable and unwelcomed. This also suggests how the wife is very territorial and is trying to impose her status upon the Handmaid possibly feeling threatened by the Handmaid, which hints to some insecurities.