quickest way to gain more followers on ig?

giveaway point is right. the other thing that works quicker than people expect is instagram search itself. put the actual words people search for in your name field and captions, not just hashtags. ig search reads them, so a niche account can get found without any reel going viral.

There isn't a quick way that lasts. The fastest legit thing I've seen is picking a narrow niche, posting reels several times a week, and being active in the comments of bigger accounts in that niche so people click through to you. Giveaways spike the number but you mostly get people who wanted the prize, and they unfollow after.