The first noble truth is realized at the moment of anuloma-ñāṇa - the moment before attainment of nibbāna. So, you don't actually contemplate it before that point. Up until that point, you are practicing what is called pubbaṅgamagga or the preliminary path.
There are four basic ways of understanding suffering:
- dukkha-vedanā - suffering as a feeling
- dukkha-sabhāva - suffering as a fact of life
- dukkha-lakkhaṇa - suffering as a characteristic of phenomena
- dukkha-sacca - suffering as a truth
Ordinary people see suffering as a feeling, and thus try to escape it by running away.
Eventually, some people begin to see it is a fact of life, not to be avoided but to be understood.
Some such people actually undertake to do so and, as a result, begin to see that suffering is actually an intrinsic characteristic of arisen phenomena; not simply because certain phenomena are painful, but because all phenomena are impermanent.
Finally, some who see thus will proceed accordingly until realizing in a momentary flash of insight that all arisen phenomena, even those one has not yet experienced, are suffering. This is what it means to realize the truth of suffering. The next moments involve the attainment of nibbāna.
So, to directly answer your question, all phenomena are to be seen as they are (yathābhūta), rather than focussing on those phenomena that are stressful. In the end, one comes to see objectively that no phenomenon is sukha (satisfying), and lets go of them all.