How to drive in rain safely?

Low beams instead of high beams. Drive a bit slower and keep your wipers on as much as you need to. Avoid puddles as much as you can, brake much sooner and take turns a little bit slower. That should keep you safe. 

Slow down is the main way you drive safely when it's raining.  Leave more room between you and the car in front of you.  Be easy making direction changes, applying the brakes or applying gas.

Same way you drive when it's dry, except slower, have the lights and wipers on. You may need to use the defogger. Do not drive faster than you can safely see ahead in time to avoid collision or other danger.

Slam on your brakes at or swerve round every puddle esp if you have a large SUV that can drive through 2ft if water.

In extremely light rain make sure you use your rear fog light to dazzle anyone following you.

you don't it can make your car slide off the road

Always keep Newton's laws of motion in mind.

Same way as how to drive in anything else safely.  Don't do any sudden moves, leave lots of room to stop, make sure the vehicle is roadworthy, obey the laws, and pay attention to any potential threats around you.

Rain isn't considered an adverse driving condition.  It reduces your visibility and traction, but not by very much.

apart from a car in good condition ..experience ...you cant buy it 

Make sure your tires have plenty of tread.  Bald tires are really bad in the rain.

Drive a little slower than you think you can.

Avoid deep puddles or muddy places.

Streets are always more slippery after the first rain after a long dry spell.

First make sure your tyres have sufficient tread depth - at least 3 mm is recommended across the whole tyre. These grovves help to move water from under the tyre increasing the tyre contact with the road.

Check that your wipers are in good condition and can clear the rain from your windscreen without streaking or smearing. Next check your lights - including fog lights if fitted.

Ready to go? Drive with a little more care than usual - your tyres will have less grip on the road so hard cornering and hard braking will be more risky than normal, you may need longer stopping distance.

Watch out for standing water, try not to drive through this, avoid splashing padestrians and look out for people who are less prepared than you. Use your lights as appropriate, your car may be less visible to other road users in poor conditions.

Stay safe!