You can spring for your own rig or pay others to do the mining for you by purchasing mining shares. Both have their respective pros and cons. Others more knowledgeable than me have written tons of stuff about this on the forum, just do a search and you'll get all the info you'll need to proceed.

There are many ways to accumulate Bitcoin. One can mine them, receive them free courtesy of giveaways, offer good and services in exchange for them, gamble what little you have in hopes of winning more (not recommended, though), and get into alternate cryptocurrencies by mining and/or trading them and eventually exchange them for BTC. This forum has all the info you need to get started on building up your BTC holdings. Happy reading!