Disaster with my flowers...  

I suggest you buy the seedlings. There are some seeds that do not grow and it is a waste of money, time and efforts.

Growing from seed is a lot of fun and I'm sorry you had such a bad time!

When I get seeds to grow, I always check Dave's Garden for the variety and see if they need to be stratified. If they need stratification, I throw them in the freezer for a couple of weeks, and they're then ready to germinate. That's an important step that a lot of people leave out.

Starting with seeds packed for the year you're going to plant them is also important. Sometimes, seeds don't germinate well if they're not fresh. Vegetables seem to be a bit more outgoing than a lot of flower seeds; but, if you can get veggies going, you're on the right track. With flower seeds, I always use a soiless mix (no compost, just peat, perlite, pine bark, type of thing) which is usually found marked a potting MIX rather than a potting SOIL.

Next year, you might want to try a technique called wintersowing. If you google it, you'll find tons of info on how to do it. Basically, you sow seeds and leave the containers out all winter. They germinate on their own in the spring and you've got tough little seedlings that don't require any acclimatizing to the outdoors.