What are the ways to promote an ERP development company?

1. Payed advertising.  The less differentiated you are, the more you'll have to pay to acquire a new sales lead.
2. Become a thought leader.  Publish quality materials on your specialism.  The less differentiated you are, the harder it will be to get your content syndicated.
3. Build advocacy by doing a good job for existing customer. The less differentiated you are the less likely they are to talk about you.

Marketing is not about telling people what you do, it's about tell them what you do that's different to the other suppliers in the market.  Look to build a differentiated value proposition.  It's really hard to do but it's the pivot point that will have the greatest multiplier when acquiring new customers in a crowded market.