One tip I got early on was try to scape the tank in 1/3rds and avoid symmetry. Keep the taller stem plants in the back 1/3 of the tank, medium height centerpiece plants like big swords and such in the middle 1/3. And keep the smaller and carpet plants in the front 1/3. Maybe plant one side heavier than the other, or have separation off center.
One tip I learned along the way, feature big, almost oversized hardscape and plant around it. Draws the eye, and then you notice all the details. Great stone or driftwood really completes a scape.
Happy aquascaping