Quickest way to increase your reputation:
1) Delete all of your posts.
2) PM all members that quoted you and pay them to delete that post.
3) Delete your forum account.
4) Never return.
That was about the rudest response I can imagine.
The OP has been a member of this forum since January. If you viewed vite's post history, you'll see many posts in Spanish. For bitcoin to become a global currency it needs participation from those around the globe. Oddly enough for some of us, the majority of the those around the globe don't speak English as their primarily language.
Specifically, what that means is that if someone uses a word in the wrong context or even if that person does something that might be off-putting, a more appropriate response is to provide guidance and to cultivate community.
vite, to answer your question properly, more information is needed. For instance, one of the benefits of having a good trust history is being able to find a counterparty willing to sell bitcoins, even in larger purchase amounts, in exchange for PayPal. If that is the goal then the best way is to start small and build from there.
There are other techniques also. The barrier for gaining trust locally is much lower than the barrier for a pseudonymous party trying to find new customers online. If there are any traders or merchants near you who accept bitcoin, try to meet in person and do a small trade. "Have met in-person" is a strong endorsement.
In addition to #bitcoin-otc Web of Trust (WoT) and forum history, there are other reputation systems. BitMit has seller ratings, for instance, similar to eBay and that rating might be helpful. Heatware is a reputation service. Ogrr.com, for instance, is a marketplace that takes another approach. In addition to being able to see ratings history and friends the service lets you see the your counterparty's BTC balance so that you as seller can at least know they have the capacity to make the purchase.
Personally, even if the counterparty has a great forum history or heatware rating for instance, that really means little thanks to identity theft. BitcoinTalk forum allows weak passwords, for instance, and many people use the same password with their forum account as they use elsewhere where security breaches are continually occurring (like Bitcoinica's incident earlier this month, or WHMCS's breach last week). That's why the #bitcoin-otc WoT is so valuable. It doesn't use username and password. It uses GPG authentication to all but eliminate the risk of identity theft.
And that's why many who transact person-to-person for any considerable amount will want the counterparty to first have an -otc WoT trust history and to be authenticated before entering a transaction.