Well, it's no really a problem there: anywhere from deep rainforest to the garden of the neighbour. In the forest itself you will find fewer specimens, but rarer species. In weedy areas (clearcuts, forest edges, ruderal vegetation) you will find more of the usual and more common species. The best places are forest edges and roads adjacent or through primary forests and mixed plantations (not those oil palm craps, but mixed cultures of several different crops) near primary forest. Secondary forest is also okay, but the species composition is closer to that of the weedy areas than to the primary forest.
Important: search an area several times: you often find anything on a particular day but one or a few days later suddenly some mantids appear. Also try several times a year, some species have discrete generations and are found as adults in the rain or dry season only. Others are found troughout the year. There is a high diversity of mantids in your area, given that some substantial rainforest ist left.
Try several methods: search by sight, by sweeping nets and light-trapping. The more methods the higher the yield.
And write me when you found something interesting. :lol: