You should focus not on what you want (settle in Singapore for the long term), but on what you offer to Singapore, above what an EP holder already does (i.e. niche skill, high salary and tax payments are NOT sufficient, but still a precondition). This could be charity work and other voluntary engagements, cultural integration into the society (i.e. that you have already demonstrated the capability to grow roots here), or (above all) the plan to produce offspring (preferably male, because of NS).
Oh you also should mention (if true) that you have no near relatives or dependents (e.g. elderly parents) whom you might want to bring to Singapore at some point - they are seen as unwanted ballast by the Singapore authorities and might cause rejection.
Another major point, which you cannot change, is your race (yes, race, not nationality!). The easier your race is perceived to integrate into the Singapore authority, the better. South-East Asian (and other overseas) Chinese are top, Indians at the bottom (interstingly, PRC Chinese are also low).
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