Essential graphs for SHM: (1) $x$ vs $t$: sinusoidal. (2) $v$ vs $t$: sinusoidal, leading by $\pi/2$. (3) $a$ vs $t$: sinusoidal, leading by $\pi$. (4) $a$ vs $x$: straight line with slope $-\omega^2$. (5) $v$ vs $x$: ellipse. (6) $KE$ and $PE$ vs $x$: parabolas, mirror images, sum is constant. (7) $KE$ and $PE$ vs $t$: oscillate at $2\omega$, always positive, shifted by $T/4$. (8) $F$ vs $x$: straight line through origin with slope $-k$. Being able to sketch all eight graphs from memory is essential for JEE.