"Always" as in what method is 100% effective in getting a response? There isn't one, but the most effective method I am aware of is getting a current happy client to make a warm introduction to a target customer that they know personally or from working together in the past. I would say this is successful for me 90% or more of the time.
I prefer to do outreach over social media if it's my first attempt at contacting them. Since people are easy to find on social media, it's clear how I found them. If I am emailing as my first outreach, they may wonder how it is I got their email address, which may not be as publicly available as their social media profiles.
I've seen other HubSpot users take the opposite approach since it comes down to understanding the person you're reaching out to, their industry, and standard outreach methods. For example, if your sector often convenes at trade shows, and participants supply their email addresses, they may be accustomed to receiving a follow-up email post-event.
Ultimately, if you feel more comfortable with one method, you're probably right 😉!
It depends on what works or is most convinient for the individual client/prospect.
You could have buyer personas that estimate what kind of outreach a particular type of prospect/client may engage with best
but I like to also be upfront and ask prospects/clients early on when we connect.
Som people like written emails, some like video emails and others like social media DMs, phone calls and the list goes on.
A great salesperson knows how to use multiple channels and selects the channel that resonates best for each individual prospect/client to personalize their experience, therefore reducing communication friction that may affect the engagement negatively.