I need help with follow liker plan & ideas

Hello, i will doing promotion for an artist on twitter. I have follow liker with some proxies and some good looking accounts to promote the main one. Now my settings are pretty good i believe but feel free to share some good ones as i am always open for suggestions. My real question is, how would i grow the main account without annoying people with spam. i've tried tweeting people with about 50 accounts interested in the niche, i've had a little success but i feel like i could do more impact some other way without spamming people. Thanks a lot!!!