1. Use speartons , meric, mage/horde of swordwrath (if possible) and again, meric, mage.
2. Slow down their economy by any way (sometimes don't work).
3. Make them busy (almost the same as slow the economy but this is against early rushers).
4. Make sure you have good, steady economy to build follow either the above.
5. Don't let ya important starting units die (like archers and early speatons and above all, miners) before ya have real army as you can make pressure on them, prevent them from going any further to giants.