Prefer light colors in fonts for a better contrast with the black background.
Don't use bold by default in normal text. Since, Vim doesn't use bold text by default. Also, some highlighters turn on/off the bold text to differentiate attributes (itemDatas) and this causes these highlighters to not look good and there is an inconsistency between bold and non-bold text.
Use common colors of Vim highlighters, for example margeta on Strings and light blue on Keywords. Also, seek to resemble the color types of the Default theme of KSyntaxHighlighting, for example, use green in dsOthers and dsPreprocessor, yellow in dsInformation, purple in dsFunction, etc.