Two suggestions: Maybelline The Falsies and Cover Girl Lash Blast Fusion. I think Maybelline Falsies deliver better results, but can be more challenging to apply. It dries really fast so it can get clumpy if you wait too long between coats. However, if you are quick, you can get some amazing results. I am a makeup junkie and nothing I try looks exactly like false lashes, but Maybelline Falsies look pretty darn good.
If you aren't super comfortable with fast application, Cover Girl's Lash Blast Fusion might be better. It doesn't dry as fast and is easier to apply. It is the one in the purple tube and is a combo of lengthening and volumizing. I think it is definitely one of the better mascaras I have ever tried.
Half the battle is proper application. If I am going for a super full look I will curl my lashes. I use a hair dryer and warm up my curler for 3-5 seconds. Curl lashes. I take out the wand and use a tissue to remove excess product to avoid clumps. Start at the roots and really zig zig the wand back and forth to get the mascara at the roots. Do this from the outside to the inside of the eye. Do not let the product dry before applying another coat. If you do, it will clump. I do two or three applications. I normally don't use mascara on the bottom lashes, but if I decide to, it will only be very lightly.
I also will combine mascara if I want a certain look. For example, Maybelline's Illegal Lengths is an amazing lengthener, but doesn't hardly volumize. Sometimes I apply Illegal Lengths first and then the Falsies for volume.
Hope that helps!