Venus is actually a better candidate for colonization in some regards thanks to its proximity to the Earth, thick atmosphere, and Earth-like gravity, and like the Earth, it resides within the solar system's habitable zone. We also know it can hold an atmosphere, and it has nearly the same mass and size as Earth. Mars, on the other hand, is considerably smaller, and would pose serious health risks to humans (reduced muscle mass and bone density) on account of its low gravity.
In the 1990s, Paul Birch proposed a plan that would see Venus flooded with over 4x1019 kg of hydrogen. This would cause a reaction with the CO2, which would in turn produce graphite and water — a lot of water. His estimates predicted that about 80% of the surface area of Venus would eventually be covered in water (compared to Earth's 70%).
The United Arab Emirates president Sheikh Khalifa bin Zayed Al Nahyan has had the nation's top scientific minds secretly toiling for years to create a new means of weather manipulation that would work more effectively in the region's extreme temperatures. The result: The biggest Ionic Breeze on Earth. Ionic Breeze devices are giant ionizers mounted atop tall steel poles and were built by the Swiss company, Metro Systems International. The devices generate massive ionic fields, positively charged ions ground back to the Earth while the negatively charged ions rise into the atmosphere. As they rise, the negative ions (electrons) collect particles of dust on the way up. These flecks act as seeds for ice crystal formation, much as silver iodide does except without the need for clouds. As long as the atmospheric humidity is at least 30 percent, the system supposedly works even in clear skies.
The surface of Venus is far too hot, and the atmosphere too dense, for Human life or most machinery. But the air on Venus thins out and cools considerably as you rise above the surface; about 30 miles up you hit the sweet spot for human habitation. The atmospheric pressure there is the same as Earth sea level (1 bar). Temperatures are perfect for Earth life too, just over 0°C.
House Ionic breeze devices within floating laboratories and manipulate the weather in order to shield the planet from solar radiation from the sun as well as increase hydrogen and oxygen within the atmosphere.