Do not feed your lawn in very hot weather! You will scorch the grass.
When cutting grass, put your lawnmower to the highest setting and leave the cuttings on the ground to retain more water in the soil and shade it.
Keep dead heading your flowering plants and roses to ensure a longer flowering period.
When in doubt, Google it. Some plants like to be pruned at different points in the year if at all. Check if they need soft or hard pruning and when.
Make a bee bath. Bees will get very tired in this season and will need a little pick me up. Line a plate or shallow tub with pebbles across the bottom to give bees something to stand on so they don’t drown while drinking. Top up with a sugar water solution. It will evaporate quickly so remember to top it up during the day.