You can compete with big companies by mainly focusing on the weak points of these companies. Make research and find out the areas they are lacking, the look for ways to improve on those areas.
What kind of audience are you trying to bring under your forum community? Create sections related to this and have engaging contents and with a proper promotion, you should have a good result.
When it comes to creating community mainly for discussion, i think building a forum would be best, but when it comes to a community for business or sharing of files and the like, i think social media would be a perfect choice.
I think it is extremely important to be able to generate revenue from your forum, with all the expenses needed to run the forum, generating revenue would help a lot.
Color choice plays a major role in website design, it not only serves as a way to create a brand identity, it also helps enhance visual experience for users.
Website load speed plays a major role when it comes to user experience. It can be very frustrating and irritating when your website loads extremely slow, it's s huge turn off for most persons
I think simplicity is key, people tend to loose track of their goal by making things too complex all in the name of design. Make your website classy and simple.