I have a feeling that you mean *playing* at Wimbledon, which is an extremely elite tournament, as are all the grand slam events. If you want to play in the first round of the QUALIFYING men's or women's singles at Wimbledon's, then you need to be *at least* ranked in the top 250-300 players on the ATP World Tour or WTA tour's computer rankings. The men have about 1,800 players in their singles rankings, while the women have over 1,100 on their's. So, the vast majority of these players are NOT eligible to participate in Wimbledon's qualifying tournament.
http://www.atpworldtour.com/Rankings/Singles.aspx
http://www.sonyericssonwtatour.com/page/RankingsSingles/0,,12781~0~1~100,00.html
Some players have decided to specialize in doubles, and the ATP has a special rankings list for them:
http://www.atpworldtour.com/Rankings/Doubles.aspx
http://www.sonyericssonwtatour.com/page/RankingsDoubles/0,,12781~0~1~100,00.html
Wimbledon also has junior [18 and under] events, so if you're already a highly-ranked international junior player, then you could play in that. Once again, this is a very, very elite junior tournament.
So, how do you get to be that good? Well, it's a long, tough road getting there. You have to have several things going for you, and not necessarily in this order.
1. You like the game enough to work on it at least six days a week. If you enjoy running around and hitting the ball, that's a positive. If you really don't like running around and hitting the ball, that's a negative. It is a SKILL sport, which means that it takes YEARS to get good at it, sort of like chess, piano, things like that. It is NOT easy, and I think you know this already. Most world-class players start by 8 or 9 years old, many sooner than that.
2. You don't mind being away from home for long periods of time; you're a good traveler. Do you speak any foreign languages?
3. You've built up confidence that can only be acquired by winning lots of matches, tournaments, and getting highly ranked in your home country.
4. You have at least one person close to you who care a LOT about you doing well in tennis. You can't do this all by yourself, so don't go that way. If both your parents approve, that's helpful; if one or both of them don't approve, that's negative. Your "helper" needs to be smart enough to keep you from getting injured physically or burned out mentally.
5. You have access to the money that is necessary to get coaching, travel, food, equipment, hotel, etc etc etc. Your financial situation must be strong [access to big money] enough so that you can keep traveling and playing for at least a couple or three years to work your way up the international rankings. [I assume that you've already worked up the sectional and national rankings in your country. Some countries used to only allow their top players to travel outside of the country to play, so whoever came from such a country would already have a high level of skill.]
6. Physically, you need to be strong enough/athletic enough to execute tennis' many demanding requirements, such as running/sprinting, throwing, twisting/turning, etc, etc.
7. Socially, you need access to people who can help you out, people who know a lot more about what it takes to move up in the rankings than you do.
8. You need a place to practice and other young people to hit with, preferably close to home. Otherwise, you need to move away from home or go to a boarding school that specializes in tennis.
9. Your behavior/sportsmanship should be very good. Can you keep your mouth shut when you're losing? If everyone on the tour hates you, that will be tough.
Summing up, you need strength in four areas: Physical, Psychological, Social, and Financial. If you have help in all these areas, then you are already very lucky, so enjoy the privilege of being able to play.
Here's a nice book on this topic: "Taking Your Tennis On Tour," by Bonita Marks, PhD.
ISBN-13: 978-0-9722759-6-5, or ISBN-10: 0-9722759-3-2.
Of course, if all you want to do is GO to Wimbledon and see the place, then all you need is the money to travel there, find a hotel or place to stay of some sort, feed yourself, and buy a ticket :-)
http://www.wimbledon.org/en_GB/index.html