A good focus technique when we have to choose from too many options is the MoSCoW technique.
It comes from the software development Agile Method DSDM and is a straightforward way of prioritizing items.
In short, we can classify our items (let’s say the importance of each functional requirement or which quick win shall one address in the first place) following this criteria:
M – MUST have this
S – SHOULD have this if at all possible
C – COULD have this if it does not affect anything else
W – WON’T have this time but WOULD like in the future
If done with the Customer – for example during an initial brainstorming workshop – it empowers him to participate actively in the decision process regarding the most adequate order of doing things (and which ones are really important).
A bit more on this here.