- The best tip are very sharp knifes, i even use some one-time-use surgical scalpel knives (because my possibillity to get them) also not thickblade. X-Acto is good.
- Be careful with the hot-glue, dont overuse.
- If really wants nice connection of foamparts without close to not seen such, lightweight wall filler (sparkel) sanding, and sanding, , perhaps woodglue to shut all possibillity for paint to get to foam, spraypaint guide layer, sanding again, perhaps more filler too? and spraypaint when feel all is good. Even perhaps a layer of clearcoat at end.
Is all the stuff for best surfaces needed? NOPE, its much work who anyway the model dont care about when in air. Its only "for show" , or if have much free time to use anyway.