You can grow btc by alot of different things. A good thing to do are forum signature campaigns which earns you money per post you post.
You need a good forum rank though to earn an okay amount but it's very easy go check it out, goodluck.
But participating is signature campaign is not a way to get a higher amount of bitcoins as the earning from there is limited and we cannot become rich with or cannot get bitcoin with which we can spend a luxurious life. If someone want a high amount of profit and want to get a big amount of bitcoins in short time then you have to invest them.
If you get some earnings from signature campaign and then make use of it like to invest in trade or any other place where it is possible (not ponzi) then your money will definitely increase and so with that you will be able to start a good business and much more.