Here are some polished title variations for your content depending on style and platform:

Clean + Professional (Blog/Guide Style)

How to Sell on Instagram: Set Up Your Instagram Shop in 15 Minutes or Less

Step-by-Step Guide: Launch Your Instagram Shop in Under 15 Minutes

Instagram Shop Setup Made Easy: Sell Your Products in 15 Minutes

Catchy + Engaging (YouTube/Video Style)

Sell on Instagram FAST! Set Up Your Shop in 15 Minutes ⏱️

How I Set Up My Instagram Shop in 15 Minutes – Easy Tutorial

Launch Your Instagram Shop Today – 15-Minute Setup Guide

SEO-Friendly (Search-driven)

How to Set Up an Instagram Shop and Sell Products Quickly (15 Minutes)

Instagram Selling Guide: Launch Your Shop in Under 15 Minutes

Step-by-Step Instagram Shop Setup for Beginners

I can also create a full step-by-step guide or video script showing:

Setting up a business account.

Connecting your product catalog.

Configuring Instagram Shop settings.

Tips to optimize product listings and start selling quickly.