It's almost impossible to find a niche that doesn't have some relevant forum dedicated to it. Then, if they have good traffic and allow it, you can implement a universal forum marketing strategy that can transform your business within a year. The entire plan doesn't have to take nearly as long as you might imagine. Of course, if you want to get the greatest amount of benefit from your marketing efforts you will need to dedicate a fair amount of time and attention to this endeavor. But that's your mindset and you have to decide what's best for you.
Many many will act the way that they normally act when they are in forums. Others will range from outgoing to shy. So, just act normally, unless you are very aggressive and obnoxious. If you are shy, it is okay to just watch things before you start contributing. This behavior is called lurking and lots of people do it all the time. It might seem too frightening to make your first post. Once you settle into it, then simply start replying in threads and always be courteous and offer value. There are several golden rules with forum marketing, and one of them is to give value and be helpful. Doing this will help someone else in the forum. People can become resentful or insecure for a lot of reasons. One might be because you think that you know everything. But it just depends on how you present your knowledge in the forum. Yes, you might know a lot about your subject, but don't come off as a know it all. If other form members are not that receptive towards you, then it will not be too good for you. It does not matter how much you know if others do not think highly of you.
When you become a forum member, only you can determine how the others will see you. You can create whatever character that you want to be. But do not get crazy with this because you cannot predict the future. If you are a really aggressive person, you can change this in the very beginning. A lot of people just are not as aggressive. However, you control how others will see you. Depending on your niche, you might want to keep a low profile. So you may want to think about this depending on your circumstances and what your goals are.
It's easy to get attached to forums. Don't get so caught my blog up in building relationships on these forums that you forget why you're doing it. Always remember that your time has value and choose wisely where you spend it. Your want the best possible return on investment for your time, after all.