Seeking for appeal letter
Should focus not on what we want (settle in Singapore for the long term), but on what we offer to Singapore, above what an Employment Pass (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 we have already demonstrated the capability to grow roots here), or (above all) the plan to produce offspring (preferably male, because of NS).
also should mention (if true) that we have no near relatives or dependents (e.g. elderly parents) whom we might want to bring to Singapore at some point - they are seen as unwanted ballast by the Singapore authorities and might cause rejection.