Yes, you can certainly promote for free (and many do), but for success it could easily turn into a full-time job. You need to engage and follow and add a lot of interesting content that would help you gain followers.
There are all sorts of tips on how to make your profile page more attractive. Use an interesting graphic, include pertinent information on how to contact you and be sure to pin some interesting content to the top of your page.
You’ll need to overcome any hesitancy you might have about following folks (you can always use a free tool like Unfollowspy to see who no longer follows you back). You’ll want to engage with followers in your niche if nothing other than tweeting ‘nice to meet you’ once in a while.
The saying that ‘content is king’ is particularly apt on Twitter and you are certainly not restricted to providing your own content. Don’t hesitate to search for trending topics that would be of interest to your niche. There used to be several hashtag analytics tools free trials are now the trend. Still, you might get a lot of a free tool like TweetReach…
You can upload your own free images (Pixabay) if, say, Forbes has an interesting article, but you think the picture is not compelling enough. Just add their link to the tweet but add your selected image as well.
Another free tool you can add to your Twitter marketing arsenal would be Sniply. You can search for appropriate content and with the Sniply extension add your own call-to-action advertisement to the bottom of the article frame.
There are free tools (with upgrades) that can help you schedule and repost content over time. Some will simultaneously post to other social media sites like Facebook. Do a search for ‘free Twitter scheduling tools’ to find something that works for you.
Remember, too, that you are asking about promoting your Twitter profile. Leads and sales will come over time. Engagement will be the key. A Twitter quiz builder like TinyInteract can help with this. No takers? Keep trying from time to time as your follower list grows.
As mentioned above, it takes a lot of work and engagement to develop a targeted Twitter following, and the same could be said for other free-to-join social media platforms like Facebook or Pinterest.
Of course, its much easier to use paid advertising to boost your profile. But the good news is that you can learn a lot by doing it ‘the hard way.’