I'd also suggest investing in a couple of pairs of maternity jeans - they're so comfy and can be dressed up or down too. I found myself living in loose, flowy dresses from mid-pregnancy onwards; they were cool and comfortable and looked cute with a little bump.
Also, I agree with the earlier comment about the belly band - it gave me so much support and meant I could continue wearing my regular tops longer because it held everything in place. And it helped keep those annoying panty lines at bay too!
Pillows are also a great investment. I found a firm pregnancy pillow that went between my knees and bumped kept me comfortable all night. But even just regular pillows can be arranged to support the bump when lying down or sitting up in bed - super helpful for some comfort when your bump is getting bigger.
And finally, maternity tights! They're brilliant if you need to dress up a bit more formally. They have a soft panel that sits over the bump and they come in different colours too.
Comfort is key - you want to feel as relaxed as possible during this special time! So exciting!