Sunday – Shin-chee-tee-en
Written as xīngqītiān xingqitian
Note: Sunday in Mandarin Chinese starts with "Day of the week" which we know is shing-chee (xingqi).
Sunday is shing-chee-tee-en (xingqitian).
To remember that the end of the word for Sunday is pronounced tee-en (tian), use the following mnemonic:
On Sunday at church, tea is served at the end (tee-en) of the pews during the service.

Tones
En (tea is served at the end) is a 1st tone with — as an accent.
Associate the tea, a 1st tone, with a string or tie or tying or knot. See Tones and Mnemonics.

The tea urn was all tied up with string.
Remember
Tee-en= 1st tone = —