clipping is a process, take your time. Take it off in layers. I like to clip a little on each calf each day.
In general- Take down the high spots, leave the hair longer in the low spots.
That'll mean peel the brisket tight, might have to leave some at the heart girth, tighter but not scalped at the rib, and taper the flank back as much as the flank hair allows you to. Ideally you end up with a straight to slightly curved belly line, but you can only work with what you have.
Same goes for the legs- tighter at the hock, longer where the bone is flat and blend into the foot. Clip in a natural curvature to the leg- this really depends on how much set the animal actually has.
For aids, use time to your advantage (practice), be patient, use your knowledge of what a good one should look like as a guide. Do your best and that's what matters. Don't be afraid to call someone to ask for help or a second opinion.