Y2527

Hi there I'm quite new to 3d printing. Starting printing a shape and having real issue with the consistency of the extrusion. The printer prints a big blob on every layer which is very visible. Also as it prints, sometimes there a little gap in the material. I tried to print a curve shape on the top and it also started coming off leaving a big hole in my print. I'm using a 0.8 nozzle to print. Any recommendations? Thanks! Yod