How does Texture Cache work in Tile Based Rendering GPU How does cache work with tile based rendering? 

Are there any tips on how to improve cache hit ratio for it? (for instance, if tiles are processed horizontally and I have vertical segments of triangles with the same texture, does it work worse for cache than if I had triangles layout out horizontally?)
Whether it's a tile based GPU or not doesn't really affect the texture cache architecture. The memory layout of texture will look like some flavor of Morton order or Hilbert curve in all GPUs.

As a result, it's more efficient to render triangles that are close to equilateral triangles because GPU memory system fetches cache lines of texels.

So obviously on tile borders, it may happen that you have to fetch texels twice. This has a small cost as tile borders are only "few" pixels.

Arguably desktop GPUs behave identically to tile based GPUs as experiments such as the following demonstrate:
http://www.g-truc.net/post-0597.html

The size of the tiles differ but both architecture actually process fragments into a hierarchy of tiles of different sizes.

When coding for tile based GPUs my recommendation is to always have in mind:


Don't switch framebuffer objects unless you really need to.
When binding a new framebuffer object, if you don't need to save the content of the current framebuffer, discard it. If don't want to load content of the new framebuffer, then you should clear the framebuffer.