Woolf's first novel, "The Voyage Out", can get overlooked because many readers and critics focus on her more experimental and more widely-read works (such as "To The Lighthouse" and "The Waves"). Although this work is not as revolutionary in its style it is still an excellent piece of literature and the traditional narrative style means that there is more direct exploration of specific themes (such as the value of the arts in society).
Most importantly Rachel Vinrace seems to me to be one of Woolf's best and most endearing characters. The reader first meets her as a young and naive girl and watches as a series of events in the book transforms her into a more mature young woman. This makes the book a fulfilling read in itself because Rachel's character progresses and develops (some would argue that progression of character is detrementally absent in, for example, "The Waves"). However I think "The Voyage Out" is not only a good book in its own right, but also a very interesting piece when read in relation to Woolf's other novels. "Mrs. Dalloway", "To the Lighthouse" and "The Years" all contain female heroines, who, despite being complex and well developed characters, could be argued to show little progression. Rachel Vinrace can be seen as a younger but similar character whose progression may thus be a reflection of these other characters' progressions to their mature and stable opinions and personalities. Even if you haven't read any other novels by Woolf, "The Voyage Out" with its engaging characters and interesting themes is well worth reading.