How to get followers on tumblr and twitter?

Advertise. Or do something insane on youtube.

Just be active and you’ll gradually get some followers.

Be intetesing.

Sing, Sing a song, make it simple to last the whole life long.

Keep your tumblr and twitter links in your email signature, business cards, about pages. Start asking your friends to follow you, then move into colleagues. And most importantly, keep actively creating great content, so when people find you they will want to follow you (and retweet, etc.)

Reply and follow other people, too. Be generally pro-active and giving in the community (make sure not 100% of your actions are self-serving and for your business—why would someone want to follow you?). It needs to be interesting and relevant.

Maybe try offering discounts/deals to your followers, or something similar.

And at the end of the day, make sure getting followers falls into a bigger marketing strategy.