One Sunday afternoon/morning/night I accompanied my wife to her workshop where she musthad to finish a job.

Had to -> obligation in the past (como tenía que)

“They had to eat” -> tenían que comer

One + week day + morning/evening/afternoon/night is the formula

While/Whilst I waited shefor her to finish, I grabed my brushes, pencils and watercolors that I wore with me, and I began to draw an antique sewing machine.

I waited for + event/action to conclude/happen
In this case, the event is for ‘her to finish’

“Whilst I waited for my sister to get ready”

“Whilst I listened for the sound of the train.”

In the end I did an nice illustration of a Daewoo industrial flat bed sewing machine in a green color.

An -> used in front of vowels: a e I o u

One Sunday I accompanied my wife to her workshop where she musthad to finish a job.

While I waited shefor her to finish, I grabbed my brushes, pencils, and watercolors that I woretook with me, and I began to draw an antique sewing machine.

In the end, I didrew an nice illustration of a Daewoo industrial flat bed sewing machine, in a green color.

One Sunday, I accompanied my wife to her workshop, where she mustneeded to finish a job.

While I waited shefor her to finish, I grabbed mythe brushes, pencils and watercolors that I worehad brought with me, and I began to draw an antique sewing machine.

In the end, I didmade an nice illustration of a green Daewoo industrial flat bed sewing machine in a green color.

One Sunday, I accompanied my wife to her workshop where she musthad to finish a job.

'Must' doesn't work here because being in the present tense, it mixes with the past tense phrasing of 'I accompanied my wife' and 'she had to finish a job'.

While I waited shefor her to finish, I grabbed my brushes, pencils and watercolors that I worebrought with me, and I began to draw an antique sewing machine.

Some word choice errors here and a minor spelling error.

In the end, I did an nice illustration of a Daewoo industrial flat bed sewing machine in a green color.

Because 'nice' doesn't begin with a vowel, 'a' instead of 'an' is the proper usage. Also, it's better to put a comma after 'in the end'.

One Sunday, I accompanied my wife to her workshop where she musthad to finish a job.

You could also say "One Sunday,", but only if you are talking about a Sunday that happened a long time ago.

While I waited shefor her to finish, I grabbed my brushes, pencils and watercolors that I worehad with me, and I began to draw an antique sewing machine.

"Wore" is only for clothes.