Let's get the obvious out of the way first. You'll probably be told to visit Wenlin Jie (文林街), which is also known as 'foreigner street'. Truth be told that although quite a few foreigners congregate here, it's still no more than about 3 dozen or so. KSR it ain't! For that we can be truly thankful.
There are lots of Western style [food] coffee shops, which are good places to sit, talk, study, play cards and surf the 'net [wifi]; lots of restaurants - all types - and a fair few clothes shops, and other shops, as well as bars.
The other reason Wenlinjie is mentioned is because it's next to Yunnan University, and has a large (Chinese) student population, and is also in close vicinity to Green Lake Park (翠湖公园). Green Lake Park has a lot of recommendations because it's fairly central, big (relatively speaking), has lots of fauna but I feel lacking in green, open spaces. The park always has lots of performances from traditional folk songs and instruments to family entertainment; people playing mah jong and cards, and English Corner.
That said, I originally found the park disappointing, because by London standards, it's small and lacks green, open spaces.
The only other parks are all on the outskirts of Kunming. Check out this thread for more info: www.gokunming.com/en/blog/item/382/kunming_park_guide
There are very few cultural activities in terms of museums, galleries, etc. Kunming is quite undeveloped in that regard. But if you're interested in local colour, there are lots of places where you can see people dancing in groups to music each evening - all family friendly and a whole lot of fun, especially Government Square (?) on Dong Feng Dong Lu (东风东路).
There are some art galleries to see around the Loft area (embryonic art scene) on Jindingshan Bei Road (金鼎山北路), which are quite interesting - plus there are a few eateries: www.gokunming.com/en/listings/item/lof_32505/
I'm still not au fait with the all the restaurants, especially as I haven't really spent time in the north parts of Kunming. Perhaps others could provide advice, or read the listings of reviews for restaurants.
As for shopping, you have extremely upscale and stupidly expensive Gingko for Western high-end designer things [clothes]; Qingnian Lu (青年路) has a lot of shops from high-end designer (Gucci) to regular, local clothing ware. Also check out Zheng Yi Lu (正义路), which also has lots of shops including foreign restaurants in the shopping malls - from Brazilian, to Russian, to Japanese.
For nightlife, there are various bars (Hump is the obvious one) and Kundu for clubs. However, the night-life is typical SE Asian fare re: opulent clubs where you stand around tables, with people drinking and smoking, listening to extremely loud and excruciatingly bad music, with a small spot to dance. You may find the experience amusing fun or unsophisticated (delete as appropriate).
If you need to get away due to Kunming sucking the life out of you, there are places on the outskirts to visit such as Xi Shan (西山- Western Mountains), Bamboo Temple (筇竹寺): www.gokunming.com/en/blog/item/1654/getting_away_bamboo_temple and Black Dragon Pool (黑龙潭): www.gokunming.com/[...] not to mention the heavyweight Stone Forest (石林): www.gokunming.com/en/blog/item/1571/getting_away_stone_forest
With all this in mind, please be advised that Kunming ain't London, Tokyo, Beijing, Shanghai, Hong Kong, et al. There isn't a great deal to do in the conventional sense, and I personally would be stuck if I had a month here with nothing to do i.e. no work / study.
Kunming makes a really good base for exploring Yunnan because there are a wealth of absolutely stunning places to visit and explore if you like to get out and about and do things. I personally think spending a month here in Kunming without exploring what Yunnan has to offer would be a waste e.g. Dali, Lijiang, Tiger Leaping Gorge, Zhongdian (Shangri-la), Deqin (if the road is open - doubtful), Lugu Hu (my personal recommendation - stunningly beautiful); as well as other places like Xishuangbanna in the SW for the whole SE Asian vibe; Puzhehei; and hiking in Nujiang Valley (along the Yunnan - Burmese border).
Hope that helps for starters. Hopefully, others can also post and provide advice.
Cheers!