It's all about priming. For any good eye makeup job, you'll want to make sure you're not doing work for nothing. If your eyeshadow is going to crease in an hour or your mascara is going to wear off ASAP, what's the point?
I've used primer ever since high school when I got my makeup done at Sephora for junior prom. It was the best day because it was this day when I was introduced to Benefit's F.Y. Eye. It is the most amazing base because after I apply this to my lids, my eyeshadow will literally not move all day long. I can go to work, go to dinner, and go out afterward without even touching up! My shadow will stay in place all day. It's fantastic. My mom tends to have a little bit more of an issue with her oily skin (though mine is pretty darn oily!) so I got her using Urban Decay's Eyeshadow Primer Potion. It works like a charm!
As for my lashes, I just became addicted to Prescriptives' Lash Builder Mascara Basecoat. It really provides a start to lengthening my lashes before I put a few coats of mascara on. I find that my lashes are fuller, longer, and stay put all day long. It may look strange at first, as your lashes look a little white-ish. But once you put on your mascara, your worries are gone, especially since the white coat dries clear. S likes MAC's Prep + Prime Lash for $13.50. Think of this product as a basecoat for your lashes - you wouldn't polish your nails without a basecoat, right! Or would you?!
Photo: F.Y. Eye - Sephora.com; Lash Builder - Prescriptives.com