Be aware that when you add ReShade the game will loose a lot of fps. As I don't have the time to test and bench everything, you have to test/bench it by yourself. If you find the right options plz post in the comments. Cheers

This guide tries to improve the visual quality of Tennis World Tour using ReShade.
.................................................................................................................................................................
Vanilla (left) | ReSHade (right)
.................................................................................................................................................................
Vanilla (left) | ReSHade with addiditional TiltShift (right)

1. Download ReShade from https://reshade.me/
2. Launch ReShade_Setup_4.2.1.exe
3. Select wttpc.exe from ?:\SteamLibrary\steamapps\common\Tennis World Tour
4. Select Direct3D 10+
5. Click yes to download effects collection
6. Simply choose the following effects:

• Clarity
  
• Curves

7. After the installation is finished start Tennis World Tour from steam
8. Ingame press HOME to enter the ReShade menu and follow the tutorial
8.1 Create a new profile by clicking the "+" (name it as you like)
8.2 Select all the effects from above with their default setting
8.3 Set an effect toggle key e.g. Roll (settings tab > general)
8.4 Set Usage Mode to Performance (settings tab > general)
9. Close ReShade (press X), you're finished
10. Have Fun

1. Vanilla (left) | ReSHade (right)
2. Vanilla (left) | ReSHade (right)

3. Vanilla (up) | ReSHade (down)

Reshade (left) | ReSHade with addiditional TiltShift (right)

Some few used anti cheat tools by developers target ReShade as cheating and might even ban you for using it - in online mode. So be aware to check first what the developers are stating regarding that case, when the online mode is finally released.

If you run into problems/crashes try the following:

• close msi afterburner (incl riva tuner)
  
• run TWT in windowed fullscreen mode

If the above didn't help...uninstall/delete the ReShade files. :(