You can rent a dethatcher or if the yard is small you can buy a dethatching rake. I would also get an aerator. I use a foot coring aerator, but there are also aerator machines that can aerate a large area. The aerating shoes don't do a very good good job, they are not going that deep and they just poke holes in the soil and does not leave room to add top dresssing or fertilizer.
Where I live we usually plant grass and do not seed. Lawn maintenance requires aerating, dethatching, topdressing and feeding twice a year. It keeps the thatch down and lets the water and nutrients in. Core aerating allows the compost in the top dressing to get into the holes and give the roots somewhere to go. It helps to reduce compaction in a lawn that will be kept for 20 years or more.
Happy gardening in Hawaii. Gardens are where people grow.