What issues were important in the presidential campaigns of both 1888 and 1892?

These were both elections featuring Grover Cleveland as the Democratic nominee and Benjamin Harrison as the Republican.  Harrison won in 1888 and lost in 1992.

The main issue that was common to these elections was the issue of the economy.  The Republicans were seen as the party of the rich while the Democrats were seen as the party of common people.  This meant, for example, that the Republicans pushed hard for a high tariff in both of these elections while the Democrats pushed for reductions in the tariff.  A higher tariff was wanted by rich manufacturers to protect them from foreign competition.  Economic issues, and specifically the tariff, were the most important issue that factored into both elections.