Olga, the oldest sister, is usually played as a dried up spinster, a sort of “worst-case scenario” for Irina if she doesn’t get back to Moscow. A better character choice might as be the now-head of the household, feeling the burden of her sisters’ frustration. She can be in dark clothing if the director sees the General’s death as recent, but drabness should be avoided. Her attitude toward he sisters should not be imperial or scornful, but tolerant, understanding, and motherly (but not supportive of Irina’s tendency to romanticism). Try to give the character a sense of wisdom (in contrast to school-teacherly like the middle sister, Masha), intelligence, and compassion. Vershinin’s visit (in contrast to the others, who are “hangers-on” and leeches) should bring out Olga’s inherent classiness and high-society upbringing (before their father was transferred out of Moscow). If you can show her humor within the sensitivity to the faux-pas gift of the samovar, you will be well on your way to playing the subtle balance in this character between grace and despair. Chekhov wrote three distinct characters here, and a good cast will accentuate the psychologically deep personality differences of the sisters, not just their age and marital status.