Placement basics that fix most tower defence losses

Most tower defence losses I've watched come down to placement, not spending. People buy the right towers and put them in the wrong spot.

Start by finding the longest stretch of path your towers can reach. A single tower covering a long straight does far more work than two towers covering short corners. On mobile especially, where screen space is tight, coverage is everything.

Corners are your friend. Enemies slow their effective travel through a bend, so a tower placed inside a U-turn hits the same units multiple times. I look for these before I place anything else.

Don't upgrade blindly. Two well-placed level-one towers usually beat one over-leveled one early on, because they cover more of the map. Save the heavy upgrades for once your grid is stable.

Finally, watch your first losing wave and rebuild around it. The game is telling you exactly where your line is weakest.