There are a lot of tools out there that can provide you with basic data analysis: mixpanel, amplitude, looker, tableau, google analytics, redash, metabase etc. Most of these enable a quick setup with your existing data, some with the tradeoff of lacking access to raw data. Price is also a factor – there are differences between the tools so make sure to choose the one that suits you most.
When we’re talking about a small-scale company, you can always use a small server, send it information about events and visitors, connect an open source visualization tool and start querying.

Generally, when you don’t have enough users to statistically measure the results it’s better to measure the quality and not the quantity. You can talk to your users, send them surveys, do usability tests etc. For example, we are now trying to improve activation for our mobile users. We still don’t have enough traffic to make fast decisions and so we make decisions based on qualitative KPIs – we do a lot of user interviews and questionnaires. We do the same for a lot of features in the product that don’t have enough traffic yet.