1. Your Avatar, the little picture which represents your account. You need to have one, it seems obvious but I regularly come across "anonymous" accounts with ghost avatars. Your avatar is usually the first thing which people know about you, in the seconds or even micro seconds where your avatar is digested it's important not to make simple, initial mistakes. You want to get to the situation where when people see your avatar they get excited
2. Make your Avatar stand out , it's only a small space so use high contrast colours.
3. Only use a photo which has been designed to be an avatar. Do not use a passport photo or the "Best Employee of the Month", type photo you find in fast food joints.
4. If your logo works well as an avatar, use it. But most don't, you may be in love with your logo but think about how it will be perceived on SU. People using SU to improve their business are not welcomed with open arms so it's best to adopt a regular user status.
5. Be bold, be striking, but don't offend unnecessarily . Your avatar should not cause offence and the use of religious or political symbols should be avoided.
6. Pay a graphic designer to put together an avatar based on your website or company logo, if you don't have the budget create it yourself but show it to lots of friends to get feedback before you publish.
7. Concentrating on quality is the most effective way to stand out from the crowd. In a competitive environment it is quality which is the most important element when it comes to attracting friends and influencing people
8. Having more friends and fans means your stumbles will be seen by more people. Stumbleupon allows you to friend only 200 people, so make sure each one you friend, friends you back. Make sure they are active stumblers too, if someone hasn't logged on to their account they are not likely to be of any use to you. Drop them and friend someone more useful.
9. If your focus for using SU is business then you are not on StumbleUpon to make friends to meet hot partners of the opposite sex or even the same sex if that's your bag. As Marlon Brando in the Godfather says, "It's only business." I keep this in mind as I use SU. Forget making friends or meeting the love of your life, that may happen, but it's not why you are there.
10. Keeping focused on business means: Not friending every hottie in a bathing suit (they are probably fake accounts designed to sucker you in anyway). Keep in mind that networking can sometimes be better described as notworking.
11. Don't get personally offended when someone does not friend you back, simply remove them and try someone else.
12. It is not a popularity contest but a way to market your brand. It's not the amount of people in your network, it's what the people in your network can do for you.
13. Learn to say no. Learn to reject, learn to say get lost to your best pal who is sending you low quality spam to stumble. People know what you stumble and you will be judged on that.
14. Focus on those why certain people are successful. Some stumblers are more powerful than others, make sure you understand why they are power users. A lot of people spend a huge amount of time Stumbling, you cannot do this, you have a business to run. But closely analyze those who get stumbles in your sector and ask yourself, how can you get them to not only friend you but to submit your stuff.
15. There is a specific culture that exists on SU and it will help if you can understand it. It's not one that can easily be taken advantage of by someone running a business. Those who make the mistake of going against this culture, rightly or wrongly can attract a vicious element on SU. Tread carefully and do not annoy the natives.
16. There is a psychological technique called modeling, where someone wishing to emulate the success of someone puts themselves in the mindset of that person. SU is no different. If you have the time, spend a whole day looking at the those people who stumble the hot stuff in your sector and beyond. Then either create similar content or expand on the themes raised.
17. Think of SU as people stumbling ideas rather than websites The power users on SU are bright, erudite, literate, curious and deep thinking people. Think less about content as something you look at, but at the ideas it inspires. Model your own content with the same concept. People swarm around ideas on SU and it's important to deconstruct the content down to its original idea; you can then take that idea and create your own content.
18. Your politics, or personal view are irrelevant, for example if you think Global warming is bogus, then raise the issue. But not in a dogmatic or "out to make people look stupid" way, but in a way which attracts people into the conversation and into stumbling you. For example you could highlight the hypocrisy of so called " green" celebs who drive a Toyota Prius and yet have a private jet which they fly their personal chef in to cook them breakfast.
19. Don't only stumble your own stuff , but make it a healthy ratio. Stumble other peoples stuff at least 5 times more than your own.
20. Learn to find cool stuff to stumble. A website called popurls.com can do a lot of the work for you by scanning what is popular on other websites. The logic being that if it's hot on digg it could be hot on SU also. However, competition is stiff amongst professional submitters to submit the best stuff, so be aware that a considerable time investment may need to be made.
21. Choose your topics carefully . SU allows you to decide what kind of areas you stumble, some other members of SU will use this list to judge whether or not you are worthy to add. Rule of thumb is to be honest and pick the things you are passionate about, just don't go crazy and keep it focussed.
22. Be polite. Yes you may have had the third cringe worthy, low life, spammer request to ask you to friend them, but good manners costs nothing and yet being rude has the danger of creating enemies with no real bonus except being a smart ass.
23. It probably does not need to be said but best not assume anything. Do not spam, do not send out random requests for people to friend you and do not submit low quality, spammy content. SU works without a real algorithm, if you submit good stuff it will rise to the top and your account will rise in value. Submit rubbish and you will get nowhere.
24. Accept criticism. When someone gives you the thumbs down, learn from it. It's not personally (unless it's the spammer you just told to get lost) it's probably just about the content. Look at the content again and ask yourself what you could have done not to have got that thumbs down. Thumbs down are rare, so when it happens take note.
25. Do not submit front pages of e-commerce sites. People are just not interested. If you have an e-commerce site, think about a blog, think about creating some interesting content specifically crafted for the SU audience.
26. You need one of two things to really take advantage of SU, time or money. If you have the time you can see down and build an effective SU strategy. If you have the money you can pay someone to do it for you.
27. Don't think that SU is the answer to your online marketing problems. It may not fit your ROI, don't get sucked into spending resources on it till you are sure it's for you. My Dad has an engineering business where SU would be of little use. The ROI would be worthless. Perform tests before you commit time and money.
28. The definition of a valuable Stumble account is one in which people visit regularly because of the useful and interesting posts. See it as a mini blog, a way to demonstrate your knowledge of your sector. As you go on, your reputation and brand will build enabling you to use your SU account to further your business.

The above article was written in collaboration with Lyndon Antcliff , a social media marketing expert .

You can find me (Dharmesh Shah) on StumbleUpon here:

http://dshah.stumbleupon.com

I'm interested in making SU friends with active SU users interested in marketing and startups.