One of the important mechanics of English language is spellings.
Spelling mistakes occurs basically due to the following reasons:
1) Phonetically two words may sound the same.
2) The way we pronounce a word.
3) Lack of root-word knowledge.
4) Incorrect placing of vowels.
5) Repetition of letters in a word.
6) Change in the plural and singular form of a word.
7) When change of tense is done, the spelling drastically changes in some cases.
8) Confusion in noun and verb form of words.
9) Confusion in "s" and "z".
10) Last but not the least lack of practice.
1)Rome ; Roam
2)Wednesday ;Wensday( wrong pronunciation)
3) Bycycle ; bicycle ( bi - twice or two or double) ; tricycle ...
4)Imagine ; imagin (wrong)
5)Coming ; comming(wrong) :: hitting;hiting(wrong)
6) fungus; funguses(wrong --- it is fungi) :: radius ;radi(wrong -- it is radii).
7) Buy; buyed(wrong-- it should be bought)
8) The most confused sets are practise and practice. Similarly advise and advice.
9) Popularise ;popularize ; criticise ;criticize : analyse;analyze ( American and Royal English is very contradictory in the use of "s" and "z")
10) We should always keep a note of the words that trouble us a lot.
--->If one is a student , he should try to make of list of the words that come in daily use like : repeat - repitition ; names of months and days! ;grammar ; stationary- stationery.
---> If one is a professional : accommodate , advertisement, committee, opportunity, performance, recommend.....