It is especially important to attack weeds early so as to avoid lasting damage. Use a Bindii killer applicable to your lawn type and apply at the first sign of attack.
Should you prefer a natural option choose a product such as Natural Beat-A-Weed which works wonders as a spot spray on lawns. Beat-A-Weed will get rid of weeds as well as moss and algae.

And with that, maintain good simple gardening practices: fertilise to build up your lawn's resistance, do not over-water and keep an eye out for beetles and grubs.
Keep your lawn looking its best without the hard work!