not just by F/U and Dm, that is not how it works … it all goes into the small details that you use to approach your idea/goal to your targets
for example : dont say in posts or dm , “hey follow me there @main account” instead say what do you think about her/him @Main account she/he is smart right ?
1- Find influncers ( that are more likely famous because of their looks and not because of something they produce )
2- filter the influncers that are prettier then you and target the followers of the influncer that is uglier then you .
1- find Influncers in your City , Country, Nation, Target their followers and their engangers
2- filter influncers that is the same gender as you or have the same taste as you ( same clothing style same music taste, close personality …etc ) target their followers
you need atleast to test all the targets and remove the bad sources ( less then 12% FB )
keep adding source and remove bad sources based on the above
1-Create account,
name it something close enough to to a fanpage
Fanpaggges.yourname or i loveyourname here
2-make the bio attractive with emojis and say something like i love her style @yourmain …etc
3- add 10-15 posts/repost
you can make the posts and add something in caption like ( hey @mainaccount notice me please 
not hey Follow me @mainaccount
4- add hashtags that are relevant to your page, names , shortnames , nicknames …etc
Buy followers and likes and comments for your S accounts
with relative comments like hey i love her so much/ i love him so much , i like her hair …etc
you dont need to buy alot of comments maybe around 10-15 each post with 50-60 likes each and 400-600 followers each account
once your S are ready to work after like 1-2 weeks of warmup then you start the bot and enjoy the results
that how you manipulative their thoughts into thinking you are big and follow you …etc
the small details not the just F/U and DM