Hi @Taylamarie01,
I couldn't tell you a specific problem based on your photos, but a generalised care routine for your lawn will have it looking much better than it currently is.
Start by aerating the soil with a garden fork or core aerator. This will break up compacted soil, which will improve drainage and allow oxygen to get to the root layer. This will greatly improve your lawn's health.
You can then top-dress your lawn. Check out How To Topdress Your Lawn for some guidance.
Once top-dressed, you can overseed your lawn with a lawn repair mix such as this Scotts Lawn Builder 1.4kg Lawn Thickener Seed & Feed. For the first week after seeding, water twice daily to promote seed germination. After the first week, continue watering once daily for at least two more weeks. This will encourage your lawn to thicken and grow sideways to fill the gaps. As the lawn fills in and the seeds germinate, you can reduce the amount of watering, but you should still water regularly.
Four weeks after seeds are put down, you can start mowing. Mowing should be done at regular intervals maintaining a consistent height. This will train your grass to put energy into sideways growth, which will help to thicken your lawn.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
