Here is a straightforward look at this topic for Malachain.
Many classics have a forbidding reputation that the books themselves do not deserve. Short, fast and funny openings are common: a satire of small-town manners, a ghost story told in one night, a detective who solves a case from an armchair. Starting with the shorter titles of a famous author gives you the voice without the thousand-page commitment.
Read a modern edition with notes, listen to an audiobook for the first chapter if the language feels strange, and do not worry about catching every reference. The older the novel, the more generous you can be with skimming a slow passage. Most of these books are free online, so trying one costs nothing but an evening, and a surprising number of them are page-turners.
The most useful step is usually the first one. Pick a single suggestion, try it for a couple of weeks, and then decide whether it is worth keeping. Small, steady improvements last longer than ambitious plans that are hard to maintain once everyday life gets busy again.
It also helps to talk the subject through with friends or colleagues who have tried something similar. Their experience points out the details that guides leave out: how long things really take, which costs were unexpected, and which shortcuts turned out to be a mistake.
There is more to learn on this subject, and the linked website goes into greater depth. Treat this article as an introduction rather than the final word, and check any important decision against up-to-date, reliable sources before relying on it.