Lakkatura is the most accessible tea garden in Sylhet — you can be walking through it 20 minutes after leaving downtown — and offers a quick taste of the tea-estate landscape without driving out to Srimangal. The estate is still actively worked; you'll see women in colourful saris plucking leaves from the bushes, factory smoke from the processing sheds, and bullock carts on the dirt roads.
There is no formal visitor centre, but the estate's roads are open to pedestrians; ask at the gate before driving in. Best in the cool early morning, when the workers are out and the light is good. Be respectful of the workers — most are descendants of indentured labourers brought from elsewhere in India during the colonial era and still living on the estate.