One thing I try to do when I'm walking around is to keep my eyes open. I don't mean keep them open just in case I'm about to step in front of a car (which is of course helpful too), but I mean to try and see what's around me. To be conscious of small details, discover things I might have previously walked past without noticing and take inspiration from those details. Trying to translate details I've seen outside into something that works for interiors is a great exercise in experimenting with different elements, textures and materials.
Sometimes it's made very easy and the connections really are immediately apparent. I took these pictures yesterday while walking around an "open studio" day in our neighbourhood. Whilst the art was interesting, what really attracted me were the details I saw in the courtyards. These small details made the outside look like an extension of an indoor living space. Potted plants, wall decorations, a sink and ornaments - the perfect indoor/outdoor fusion.
In case you were wondering, the indoor pictures are of my old and rusty garden chair which I have in front of my dressing table. I think it's the perfect combination, non?