If you want to create an online reputation for selling internet marketing services you first need to understand what internet marketing is. Once you can effectively do the marketing on your own websites it will go to show other Clients how effective you truly are. Think of it as providing a statisical portfolio.
If you got penalized by any google update you have a long long journey ahead of you. Read as much as you can about SEO best practices and begin implementing them on your website(s). It will take time and patience and you probably won't see results for 6+ months. Keep in mind most people that got hit by Panda were generally victims of creating spammy content and spammy links. You are going to need to disavow those links and focus on creating quality content to reverse the damage that has been done. Depending on how bad you got hit, it may be worth your while to scrap the website(s) hit by Panda and start over fresh.