What’s the age difference between? As over 25 years they don’t like it. Has she got a dependant here in Thailand? Has she got 60k in her bank? All of the above are big factors in the visa. Money in bank you may think is not good. That money means she can just get a flight back if you split up.
Most visas now are sent to India to get processed and they get 15 minutes to do it apparently
I did about 8 photos of us together and no alcohol in the photos. Proof of conversations on line or WhatsApp. She has to have land or dependent ( child is good) as far as I can remember. Normally not more than 25 years as they look at the age thing. Don’t load it with to much information as the Indians who check it only have 15 minutes to look at it. Label it as well with coloured labels with what you have like photos and cohabitation. Also she will need money in her bank. As they want her to have money to return if she needed if things don’t work out