I couldn’t resist since I was just a MOH this past March!
First, what definitely helped me out A LOT was simply just asking the Bride what she needed help with and what she wanted to do for her shower/bachelorette parties. Most of the actual wedding planning was taken care of by her and her groom. I mainly helped with helping her say yes to a dress by showing up with her mom, the bridesmaids etc to ‘aww’ at her in the bridal boutiques.
Since you’re out of state, that may make things a little more complicated in regards to planning the Bridal Showers, Lingerie Showers, Bachelorett etc. Of course not all brides want all of these events. My Bride wanted a shower and a bachelorette so I was in charge of organizing it (along with the help of the rest of the bridesmaids). This can be a pretty big financial burden (I spent a total of about $300+ on expenses of being a MOH) so DO NOT be afraid of asking the wedding party to help (mom, mother-in-law, maids). Her MIL got the cake, her mother provided for the catering and the maids and I took care of the decor.
For the bachelorette, definitely ask her for ideas on what she would like to do and what she does NOT want to do. I had a friend that wanted a girls/spa night and then another bride that wanted the whole Chippendales full meal deal.
Of course all of this depends on how involved she wants you to be, especially taking into consideration the distance. If it’s a low-budget wedding and all you really need to do is stand there with the dress she picked, awesome. I actually would have preferred that to all the drama with the other maids. If not, always try to have patience if she makes a reasonable request from you. And reasonable means just that. I once had a friend tell me she had told a bridesmaid to lose weight!

Big no no!
And of course, if at any point (preferably earlier) you feel you cannot fulfill the role she wants you to play, you are absolutely free to decline. In the last wedding a few bridesmaids declined due to the expense and/or busy school/work schedules.
Good luck and stay calm! Use pinterest!