Since you are starting to find an agent, it is obvious that either you are already a famous artist, or you want to make your work famous. If you are already a famous artist, finding an agent will not be a problem. In fact, there will be agents everywhere who will want to become a part of your activity.
Since a famous artist will have almost no problem getting an agent, the one who wants to get famous will be the one looking for one. Therefore, if you are looking for one, then you first need to make up a portfolio of all the work that you do.
Try to gather each and every project that you have manage to pull off, put it in one file and try to show it to the agents you want to work for you, or the ones who are looking to work for some artist.
Since it is not too easy to find an agent manually and looking for one might take ages, try to look for agencies that are ready with many agents who want to work for different and emerging artists around the globe.
Try to go for the top cartoonist agencies. They know exactly what to do with your portfolio and what to do with artists of different calibre. Don’t ever underestimate your talent. There might be a day when one of the best agents around the globe are helping you find work and helping you sell your art.
When all hope is lost, the internet is always there to play a role in your life. Try going through different websites of different agencies. If that doesn’t work, try to look for different agents over social networks. You will most definitely find a good agent in one of the websites that you search for.
In case all the things above fail, you can always advertise yourself. Either do it on the social media over the internet, or around the area you live in; you will definitely see people applying for a job. Obviously, you will be paying them for whatever they do and they will be working for you. Hence, don't ever lose hope.