Before any adjustments can be made, you'll need to look at a failed print to see what the problem is. It could be your bed not being perfectly flat, or simply that the nozzle is too far away from the bed for the first layer.....or even that the piece your printing simply has too little flat area for the bed to hold.
Look at the bottom of your failed part.
Is it smooth...mirror smooth? If not, the nozzle may be too far from the bed.
Does the bottom look the same all over....or does the bottom get slightly rough towards the curled edge? If so, your bed may not be level.
Look at an edge between the bottom and a vertical side.
Has the first layer been squeezed out to form a small lip? If so...and I think it won't be...then the nozzle is too close to the bed.
Level the bed using whatever system is best for your printer. Nozzle height can be adjusted in settings....the Global-Z setting on the GCode tab......adjust negatively to lower the height, positively to raise. NB negative values are valid!
With PLA, you need to have your cooling fan off for the first layer, then set to 100%. You could also try increasing the first layer thickness to 150% or more, and slow the first layer speed down to 50% or less.
Finally, you could always use a brim....two or three outlines, one layer thick, offset zero.