Before leaving a good conversation, it’s imperative that you lock in the contact. People don’t carry business cards as much, with a lot of folks simply using Instagram. That’s alright, as long as they follow you back right then (if they don’t follow you too, you’ll be in the pile with the rest of their followers and DM’s might go unnoticed). However, it’s best if you get a phone number and text them that minute so they have you in their phone. Once you’ve made the contact, give it a day or so and be sure to follow up. People are busy, and they forget things easily. Solid follow ups are the best way to make sure you have a lasting connection and ensure your conversation from the previous day doesn’t just fade into the void. Something simple should do the trick: 

“Hey ____, was great to connect yesterday. Looking forward to working on ____ with you” 

Over time, it’s also important to keep in touch with relevant contacts, even if you haven’t done anything together in some time. For the heavy hitters in my rolodex, I like to try and touch base 2-3 times a year just to check in and see what’s new. Who knows, they might be working on something I can help with or vice versa. Once you’ve formed a good connection, it’s important to make sure it lasts.