I would recommend starting by buying an airplane ticket, and book the first 2-3 nights in a hotel you like. From there you will find long-term house.
If you don't care (yet!) where to go, I think you could do something like read some history about the places, YouTube, what to do, what to eat, read some blogs ... and decide which one you like the most or its more interesting for you.
I started with Ubud, Bali, a dream for me. Hubud its ok, too expensive? I don't know... bali its so special ...
Right now I'm in Kuala Lumpur, I didn't thought in staying here, but it is an amazing city, so I will delay my route to north Penang, Langkawi and then Thailand.
Everybody loves Chiang Mai, but it seems too easy ... I needed a little bit of adventure before it.
Where will you go?!