Here's my rule of thumb on fundraising.
1)You are an expert in building companies (you've done it before, can do it again) - this would typically be the case of repeat founders who've raised funds before
2) you are a domain expert, or have an idea which you think you are the right person to execute
For 1) as most people have pointed out things are a lot easier (relatively)
For 2) either you: a) have shown you are on the right track with customers (traction) b) prove you are the right team for the job
Again, a) makes it a bit easier to go to institutional investors. If b) the people who can be convinced of this would be the ones who know you and therefore trust you to do it (hence Friends and Family) Other option is people in the relevant industry who believe you know what you are doing (uncharitably, the Fools portion of FFFs)
From what you've told us so far, you are not seed stage. You are pre-seed as they like calling it in Europe. Institutional investors are a bad fit for this stage. Hence FFFs would be your best bet.
I would recommend accelerators, but very VERY few of them are actually worth it. But that does give you a leg up in the ecosystyem, by allowing your network to expand rapidly