Tuesday – shing-chee-ar
Written as xīngqī'èr or xingqier
Note: Tuesday in Mandarin Chinese starts with "day of the week" which we already know is shing-chee (xingqi).
Tuesday is shing-chee-ar (xingqier).
To remember that the end of the word for Tuesday is pronounced ar (er) use the following mnemonic:
I wish you wouldn't chew (Tuesday) the artwork (ar).

Tones
Ar (artwork) is a 4th tone with \ as an accent.
Associate artwork, a 4th tone, with lowering things like trip or slide down. See Tones and Mnemonics.

Imagine someone throwing famous artwork down a slide.
Remember
Ar = 4th tone = \
Examples of xingqier (Tuesday) in sentences:
Xia xingpier jiangyao kaixue - School will begin next Tuesday.
Xia xingqier hui bu hui tai chile - Will next Tuesday be too late?
Wo xingqier hui qu nali - I'll be there on Tuesday.