This is my Trostani deck.

The goal is to balance small 1/1 and 2/2 weenie production with some larger 3/3, 4/4, and 5/5s sprinkled throughout for extra power. There are plenty of populate options, as well as cards which scale with creature production and number such as Champion of Lambholt and Wayfaring Temple.

A major combo is Panharmonicon + Parallel Lives + Phyrexian Processor . Pay a high life total, then get it back four times over instantly for two big creatures. Populate and get that life again. Combo that with Ajani, Caller of the Pride + Cathars' Crusade for a massive life total and army.