@kate.poisonglen stated the general ways. To add, here's how you can advertise in Bitcointalk:

1. Make an Announcement Thread about your Exchange - since your account is a newbie, it would be better if you'll upgrade to a Copper Member to be able to post images. Read more at Newbies can now pay a small fee to enable images
2. Advertise on this forum via ad space - there's an ongoing auction now, check the details at Advertise on this forum - Round 255
3. Signature and Social Media Campaigns - they have mentioned it above. I just want to add that you should hire a trusted campaign manager for this, not really necessary but recommended (check List of Campaign Managers)

• Signature - Participants will be wearing a signature representing your exchange and it will be exposed in the forum every time the participants make a post (for ex. mine, I was wearing a BQT signature below)
• Social Media - Participants will like, follow, talk about your service on Facebook, Twitter or other social networking sites