My problem is how to make it popular and so that i can earn some money to maintain the hosting :D
Making it popular is easiest part. Hardest part is making the forum user-friendly. If you add some heavy template, bunch of modifications, copy-paste forum descriptions from other forum. You can say bye to that forum.
But,
I'll use vBulletin 3.x as an example, if your site isn't related to some particular theme, e.g. If its just a warez forum, you can use dark colors and light colors. In my case, I can't use dark colors because my forum is retro related. So the colors need to be "retro" , and the design itself.
If I was you, I'd read more about vBulletin's template structure, and I'd customize the default vBulletin template. It's quite easy, you just need to know CSS, and you need to know what stuff you can remove, and what you can't. You gotta be careful especially when you're deleting IF statements, sometimes IF end tag gets lost in the template. So you just count how many IF statements are there in template.
By default vBulletin's style is fluid, and that's how it's supposed to be. If you want to have a popular forum you need to care about details, clean header, clean template, clean decriptions, and good administration is all you need to have. If your site gets famous you wouldn't need to care about hosting because someone would probably sponsor your website.
There are cases on some forums that Staff members are mentioning religion in negative context without constructive criticism, insulting other members, etc. That's what you don't need on your forum.
