Connect a Google Sheet of your contacts so follow-ups and campaigns have someone to go to.
Your contact list is the one thing nobody can set up for you, because only you know who is worth following up.
Download the sample sheet and open it in Google Sheets. Keep the first row exactly as it is — those column names are what the importer looks for. Delete the three example rows and add your contacts.
A name — firstName (or firstName and lastName). A row without a name is skipped. Add an email for anyone you want to write to; a contact with no email is still imported but cannot be emailed.
Two columns are worth the extra effort. status (Lead, Client, Cold — your words, not ours) is how you pick an audience later, so a campaign can go to clients without going to strangers. lastContactDate is how someone gets flagged as going cold. Leave it blank if you do not know — a made-up date is worse than none.
Add any column you like. Anything that is not one of the standard names is saved on the contact under the heading you gave it, so you can filter on it later.
You can go on editing the sheet whenever you like; changes come across on the next sync.
Once a day your list is re-read and anyone who has gone quiet is brought to your attention, with a draft follow-up ready. The draft is only a draft. Nothing reaches a customer until you have read it and pressed send.