It might sound strange, but as an example, I found that creating physical space by getting rid of years and years of accumulated useless possessions, by itself made me feel lighter and freer mentally. Happiness isn't something we find 'outside' it's what remains when we get rid of things which are blocking us from feeling it. You start noticing things you didn't while your mind was focused on the things that burden you, and these can be a source of renewed joy.