I plant sweet peas in October. Most varieties need to bloom before the spring weather heats up. Al

They like them some good soil, so incorporate some good stuff in your planting patch. Maybe even dig down a foot.
Even 5 linear feet of a sweet pea patch should give you more than enough bouquets, so a small amount of work turning and sprucing up your soil is worth the effort.
I put the seed in a glass of water overnight before sowing, which I do sometime around Halloween. Sow a little more than an inch deep and maybe 3 or 4 inches between seeds...you can thin later if necessary.
The only other tip to stave off disappointment is when seedlings emerge, they must be protected by some sort of caging from birds, which will nip the seedlings when small. Once the seedlings get to 5 or 6 inches tall, they are usually safe and protection can be removed. It is also a good idea to put in your climbing structures early...if yours will be climbing a fence, perhaps you can just put up strings or netting or chicken wire for them to climb up...sounds easy. It is easier to have these climbing aids in place before the sweet peas grow too much.
Sow in Oct - Nov, flowers from May to almost July. Garden jewels that everyone loves.

If you do not bait for slugs when you plant, and refresh as needed you may not ever see a sweet pea. Some new gardeners complain they "can not grow sweet peas" or that their sweet peas "never germinated" because the slugs devour them as they emerge. Al

...And mine got so completely decimated by aphids last year that I needed a hazmat suit to pull them out. I'll be spraying with neem from the start next time I plant them.