This is a work in progress, and contribution is encouraged. Please feel free to discuss in the comments and provide feedback to contribute additional information. It would be great if this post was community driven and evolving over time.
This is huge. It's number 1 for a reason. You need good content. With the exception of really attractive people and/or celebrities, no one want's to see 100 selfies of you with the doggy filter from snapchat. Sorry.
It doesn't matter what type of pictures you're posting, learn the basics of composition, learn how to edit photos, learn how to edit movies. Spend time learning about "the rule of thirds", "the golden ratio", and other composition techniques. Watch youtube videos and practice editing your images. If you are producing content that is visually appealing, more people will want to follow you.
One day you post a picture of coffee, the next day you've got a shot of you skiing, the next, maybe you've posted about video games. How many Coffee drinkers do you think care about video games? Or gamers want to see someone skiing?
This isn't compulsory, but you're going to have an easier time finding and keeping followers if you have a specific niche you fit into such as Landscape photography, Portraits, Lifestyle, Mom's, Travel, Comedy etc
At the same time, if your pictures show a consistent tone/style, people will know what they're getting into and may be more willing to follow you.
This doesn't mean you should post 100 pictures of coffee (though if you pull it off well that could be a great novelty account), you can break up a monotonous theme with pictures of something else. Post a lot of coffee? Why not post pictures of cafe's or great places to have a coffee?
If you already have an account, this might mean you need to curate your wall a bit and delete irrelevant pictures!
3. TIME / ENGAGEMENT
Time is the second most important thing for gaining followers. Both in the sense that the longer you spend on Instagram, the larger your account will grow, and also the more time you spend interacting on the app, the faster and bigger it will grow too. Do not jump in expecting your follower count to grow over night, or even significantly in the next month. Gaining follower's is accumulative - the more followers you have, the faster you will gain them.
Start by checking out hashtags, and specifically the hashtags you post to. There's nothing you can do wrong here - the more pictures you like, the more chance someone comes and checks out your profile.
On top of that, why not comment at the same time? Try and make an observant comment about the picture and not a 3 word generic comment that could fit on anyone's picture, hell make it a question about the picture! That way they will be more likely to check out your page and interact with you further. If someone likes your pictures, go and like some of theirs! You might gain a follower just by returning a like!
Keep in mind when you start a new account, Instagram will not put your images into the hashtag feed - this is to prevent bots and spammers making new accounts all the time. Be patient, they will start showing after 2-4 weeks. Use this time to get a bunch of images ready to post and plan your hashtag use.
Instagram gives you 30 hashtag spaces to use in the picture blurb. Use them. If you're tagging other accounts you may not get 30 spots, but use as many as you can.
Make your hashtags relevant. Check out your competitors hashtags and see what they use and who they tag. Steal a few of them, try and find your own.
Tag the big curator accounts - if they feature you you may gain a small amount of likes and followers, but don't expect anything big - the real reason is that when you tag them or use similar hashtags, you will hopefully appear in the explore feed of everyone else following that account and/or liking those hashtags.
For help finding hashtags check out: displaypurposes.com
5. BEST TIME TO POST
This is tricky, because Instagram has changed the algorithm on how it shows posts. However, most would agree this still matters a bit. You want to be posting when your target audience/followers are most active. This is usually early mornings/late at night depending on where you are in the world. There are many apps available that will tell you the best time, but their reliability or accuracy is not confirmed.
6. POST FREQUENCY
This point is more relevant to getting followers quickly. The more posts you make, the more often your content is going to appear, but do not feel like you need to post every day if you do not have the content to share. Quality over quantity.
In saying that, if you want to go this route and you have ample content to share, try to post once a day to help keep yourself visible. If someone has liked your content, you are more likely (basically guaranteed) to show up again in their explore feed at some time. If your content keeps showing up they may follow you. If they are consistently liking your images, regardless of following you, then you should also be appearing in their followers explore feed.
Pictures that a longer vertically than horizontally utilize more screen real estate, and therefore spend longer on the screen when scrolling through a feed. Users have suggested in the past that they notice more likes on pictures that are orientated this way.
A comment pod is made up of about 10-15 people. This group always likes and comments on each others pictures. This becomes most beneficial if it is done as soon as a picture is posted as it helps boost the instant visibility of the post. The more followers each member has, the more benefit it is to the person who posted the picture.
Usually these pods exist via the DM feature on Instagram. When someone posts a new picture, they also share it to this group so that the group is notified and can instantly go and like the image.
These pods work best when everyone in the group has the same niche, as it means everyone's followers are more likely to also like the content.
A much hated tactic by many, but without a doubt one that works. I discourage the use of this, but it is such a popular technique it needs to be stated - at the very least, so you can understand when it happens to you.
The idea behind this is that you will follow a user and they may follow you back. After 2-4 days you unfollow them and hope they don't notice, leaving them following you.
In reality, why bother unfollowing them? Just follow them and like their images whenever you can. You'll come across much more genuine and you'll also avoid the risk of losing them as a follower.
This is considered a scummy technique to use by many, and with the amount of people that use apps to keep track of followers, it is less likely to work.
First find large accounts that are offering similar content to yours. These are basically your direct competition and already have the followers who are likely to follow the type of content you post.
Go to their followers list and start going through the followers pictures and liking/commenting on their photos starting from the top. These people are currently active and recently following others. That means they are more likely to follow you.
I haven't tested this, it's just an idea and concept at this stage.
Create your own relevant hashtag. For example "#Bleachmyfilm". make sure you use it with every single image you post.
When you like an image, Instagram makes note of what hashtags are associated with it. This is one of the ways it suggests images in the explore feed. So if someone has liked an image with your hashtag, there's a better chance your future images will also appear. If they are appearing often and being liked consistently, this is helping boost your like count, in turn giving you more visibility and the potential for followers.
That wraps it up! Lets be honest, we all strive for followers! So utilize these methods to jump ahead of your fellow Instagram users. If you have a method that I didn’t mention comment it below!