Hello, this might be common sence but I figured many might not think about doing this. Did a search and didn't find anything on this.
You need enchanting at a relatively high level. The more recipes you have the better. Now, go to your AH and buy some armor/weapon vellums (remember to get the right rank). I'll make an example here.
On my server Scroll of Enchant Boots - Icewalker - Item - World of Warcraft sells for around 80g.
The mats needed to make it is 8 Infinite dust and 1 Crystallized Water. 1 Infinite Dust is 4g and an Eternal Water is 8g. Armor vellum III costs around 10g. That makes the cost to make this scroll about 43g. That's a 37g profit.
So what you need to do is just check the prices for enchanting mats/vellums and scrolls and you can work out the enchants you'll earn the most money on yourself.
It's a very easy method that requires very little work. As I said it's mostly common sence but many might not think about doing this, hope it helps.