Rescuing a drowning person is the last resort and you should do everything possible to avoid getting into a dangerous situation in the first place. If you have to make a rescue attempt, think of your own safety first and never put yourself in danger. If the rescue is too dangerous, wait until the emergency services arrive.
With a long stick, a scarf, clothes or anything else. Crouch or lie down to avoid being pulled in.
Test the depth with a long stick before wading in and then use the stick to reach out. Hold on to someone else or the bank.
A rope is best - you can then pull in the person. Otherwise throw something that will float - a ball, a plastic bottle, a lifebuoy. This will keep the person afloat until help comes.
Use a boat if there is one nearby and if you can use it safely. Do not try to pull the person on board in case they panic and capsize the boat.