So some of the words in RTK book has many uncommon English keywords even if English is my mostly used language(learnt it as 2nd language though) . Every time I encounter such words I search the meaning on an online dictionary then put it to my story too.After 2 reviews I completely forget what does the "odd" keyword mean thus making me not able to remember the kanji after a number of reviews.

I even sometimes change the keyword to a more common word as long in does not conflict with the others. Sometimes I modify the key word .
for example
appellation->appellation(act of naming)
rectify->rectify(to correct)

. . . .but doing this too many time would sometimes conflict with other keywords too.

Such words are like

-turf
-rectify
-wherefore
-reparation
-fell. . . .keep on referring in to fell as in fall not fell as in punching or striking.
-appellation
and some more. . . .

Got any tips to remember the English meaning of the English keywords easily?
Also how to deal with 2 different keywords that almost have the same meaning(like use&utilize)?
Any help is appreciated. . .

Thx

If you know a word in Japanese that uses the kanji I might suggest that, I find that using japanese works very well in that type of situation. That might work for both of your problems.

For the English word specifically, there were a few English words or objects that I did not recognize just sitting out there (never had any use for a lidded crock, so I didnt know what it was when I came across it), and so I just went with what it sounded like to me and made a story from there. It's a bit lazy, but that way I made a story based on something I knew and understood instead of some definition that I didnt know in the first place.

But the Japanese keyword advice is what I would recommend most if you are far enough in your studies, it usually helps me more than some obscure piece of vocabulary

If it's your second language, why not add your native tongue?
Like "fell (faellen)", "ford (ueberqueren)" for German. I do that for stuff I find strange, plus I added a Japanese field, where I can put a vocab item that uses the Kanji, in Hiragana, like 集　あつめる
No problems with that.