It doesn't require 10 years of climbing to attempt Everest. 2-3 years could be adequate if you climb very often, including some high Alpine climbs. But you should still take your time to learn the skills and enjoy the practice on various mountains around the world. It's a longer, yet much more rewarding approach to climb Everest.
Buy a guidebook for various climbs and routes in your neighborhood and start practice what you've learned.
You don't need to be a skilled rock climber to climb the Himalayas since the technical parts of alpine mountains usually are different from rock "tip" climbing. You will wear bulky shoes and clothing - the rocks will be rougher and wider.
But you need rock climbing skills to know the proper techniques. It will make your climb so much easier.
Practice everywhere. Go outdoors, at evenings and weekends. It's a neat feeling to climb a steep, dark, wet and cold hill at night, and then dress up in the car for a fancy dinner at an upscale restaurant!
Climb while spending a weekend at the in-laws summer house. Behind the mall. At school brakes. In the park. There are rocks to be found everywhere. People think that you are crazy? Don't worry about it. You are about to become an Everest climber!
Bring climbing gear with you on vacations. We've had some great rock climbs in really unexpected places like the Seychelles. Make climbing a part of your every day life. 10 minutes here. One hour there. You have the time.
After you have practiced some rock climbing on your own, say a month or two, you should follow up with a class in aid climbing. It takes just a day or two and will introduce you to further techniques in artificial climbing and pegs.
These skills are specifically suited for difficult walls and tricky sections. With these techniques, you'll get in and out of everywhere.
You have climbed for around, say - 3 months, and if you started at summer and live in a temperate climate, now is the season to take a class in ice climbing. This course takes anything from 1-3 days, depending on travel. You will learn to use ice- screws, snow belays, crampons and those cool ice picks. You will be wearing hard boots and learn to climb in heavy weather gear. The ice will shimmer translucent blue and green, you will be mortified, but in the end you'll make it and then transform into Superman, ready to sign autographs!
Following the winters ice-climbs, it is now spring and a good time to join a guided expedition to a high mountain. Denali in Alaska is a good one. The climb is around 2 weeks, season ranging from May to July. You will learn to deal with cold and foul weather, altitude, to pack light, to melt water and prepare altitude food, how to set up camp, what gear to use and how to use it.
Also, you will learn how you respond to altitude - what is normal and when to be alarmed. You will also learn to handle various mountaineering problems, medicals and alpine illness preventions.
Since we had already attended a mountaineering course in the Mount Blanc massif, we took on Denali alone. Reading the book "Surviving Denali" (Jonathan Waterman) prior to the climb was of great value to us.
It's time to make your own expedition. Aaargh! Take on an easy mountain: Cho Oyu in Nepal and the likes. (But never underestimate ANY mountain). Practice what you learned when you were guided. Good time to climb Cho Oyo is in the fall, September/October. Aconcagua, South America, is a favorite in the spring.
Ready to go. Here is how...