A nonexpert should be very careful in stating and using hadith.

Checking the authenticity of a hadith is not simple and needs expertise. There is an Islamic science that studies hadith and their authenticity and it is dependent on several other Islamic sciences.

Hadiths are historical documents. The way to check the authenticity of a hadith is similar to the way of checking for the authenticity of other historical documents. A major difference is that many hadith has been preserved orally and not in a written form at least for the early centuries so there is no written document dating back to the original time the hadith has been stated. But still, some means of checking the authenticity of documents still apply, for example, the existence of multiple independent lines of narration from the source increases the confidence in the authenticity. Usually, the persons who have narrated the hadith are also important for confidence.

Another basic rule for checking authenticity is that hadith should not contradict what is said in Quran so one also needs to be knowledgeable in Quran and its interpretation which is again a non-trivial Islamic science.

There are several major collections of hadith. Some of these are solely a collection of all hadith that the author was aware of without vetting for authenticity (the main reason making all claimed hadith available for experts without bias). Others are collections where various amounts of vetting are performed. There is some hadith collection which is considered more reliable (though even in those books you may find contradictory hadith).

Shia and Sunni often have different collections because they consider different people in Islam to be reliable sources of hadith, e.g. Shia does not consider a person a reliable source simply because he or she was a companion of the prophet. In cases where there are contradictory hadith (and historically we know there were because of internal wars between Muslims not long after the prophet has passed) one needs to either choose a source to rely on and reject the other or possibly accept only those hadith which are agreed on by all sides.

The Sunni consider the following collections as reliable:

Sahih Bukhari by Imam Bukhari, Sahih Muslim by Muslim b. al-Hajjaj (d. 875), Sunan al-Sughra by al-Nasa'i, Sunan Abu Dawood by Abu Dawood, Jami al-Tirmidhi by al-Tirmidhi, Sunan ibn Majah by Ibn Majah.

On the other hand Shia consider the following collections as reliable:

Kitab al-Kafi by Muhammad ibn Ya'qub al-Kulayni al-Razi,Man la yahduruhu al-Faqih by Muhammad ibn Babuya,Al-Tahdhib and Al-Istibsar by Shaykh Muhammad Tusi.

Even if you take a single collection from the 9 collections mentioned above you may find contradictory hadith. I personally suggest you be very careful about narrating a hadith unless you have studied the required sciences to be able to distinguish between authentic and non-authentic ones and when in doubt do not accept a hadith following Quran's advice (c.f. verses 17:36, 29:8, 31:15), particularly when you see it is not consistent with Quran and hopefully God will guide us to his path. (We are quite sure that Quran is very authentic, although we know there have been minor differences as we have around 14 recitations of Quran, the differences between these narrations are small and reasonable considering the fact that Quran was not collected as a written book and was preserved orally during the prophet's time.)