The first-position arpeggios
Here are the arpeggios to know now — the broken chords of the keys you're playing. Each is just ^1 – ^3 – ^5 – ^8 of the scale, and each uses a clean first-position shape.
G, D and A major
Notice they're the same shape: open string, high 2, next open string, 3rd finger. Learn it once, move it across.
C major and E minor
Two octaves — the same shape twice
The two-octave G major arpeggio runs the first-position shape once on the G/D strings, then again on the A/E strings:
Try it
Try
Play the G major arpeggio up and down, four times, slowly, listening for the ring on the two open strings and the two G's. Then do the same for D major (even more resonant). Then C major — no open strings, so use your ear hard. Arpeggios are where you find out whether your 3rd finger really knows where G lives.
The usual mistake
Rushing the skips because they feel harder than steps, and landing the 3rd finger short (flat) after a jump. The notes of an arpeggio are further apart than a scale's, so the hand travels more — go slower here, not faster, and check each landing against the open strings. The other mistake: a bumpy bow at the string crossing in the middle. Keep the bow arm moving smoothly across; the crossing should be seamless, not a lurch.