Do you play guitar then? Standard tuning on guitar is, "E A D G B E" The bass guitar standard tuning is, "E A D G". The violin standard tuning is, "G D A E". (same as the bass guitar but backwards). Hope that helps a little to transpose your guitar chords to the fiddle? It''s all the same whole steps and half steps.

Wait, I read your post wrong...So you play violin then? Same as I said though...

here's what I think;
at the bluegrass festival I attended once they said first know what key you are in....this means if you are playing a tune in G (the most popular key for guitar music) , you need to know that scale....7 notes in the key. Those are the notes you can choose from when playing along. If you want to add double stop "chords"(since a chord is at least 3 notes traditionally) you can use the root of the guitar chord and its third. When I played the G chord progression which was G, C, and D I played the root and its third only lower than the G I was playing if that makes sense?
So it was a G (root) and a B (third) but the B was first finger on the A string and the G was the second finger on the E string. Its a super simple double stop to play too.
To play the C d.s. all you have to do is scoot your fingers over to the D and A strings and keep the same shape for your fingers. now the first finger on the D plays the E and your second finger plays the C.
To play the next d.s. in the progression the D you can then slide your fingers towards your face a step so you can play the D on the A string with your second finger and the F sharp on the D string, yup same finger position.
Super easy to do and you can quickly change between "chords" to match the ones the guitar is playing...so to sum up...you have 7 notes to choose from to ear out a melody for your solo or accent playing and you have 3 double stops to use as a progression to chuck too to accompany the guitar chords.
I hope this helps and isn't confusing.

The Key of A is the second most popular guitar key for songs and its progression is A, D, E and the finger shape of the simple double stops are the same as the key of G just make sure your second finger is on the root note ie A, D, E for each chord. Same L shape pattern as the G progression explained above.