When it come to growing plants from seeds, there are several things you must look at. First check the date on the seed package to make sure of viable seeds. There is too much time involved to get seeds that will have poor, if at all germination rate. Next, ask yourself if the plants are suitable for where you intend them to go, e.g. Soil type, light needs, moisture needs, etc. Have a soil test done. What type of soil is it? Does it meet the needs of what you want to plant there? Make amendments if needed and break up the surface to allow the new plants to take hold. If possible do not plan a garden where water run-off occurs or at the top of a hill or slop that the water runs off of, unless you are planting things that require these moisture types.
Check the package for the correct germination requirements. Some seeds need to be tricked into thinking they have gone through a winter by refrigerating them, some have a hard coating and need to be soaked or nicked first, some need bottom warmth (this can be done by putting them on top of the fridge). Make sure you check the planting depth, some seeds need light to sprout, and these are sown on top of the soil. Most seeds are planted at a depth of 3 times the size of the seed. Some seeds do not like to be moved and should be planted directly where you want them in the garden. Also make sure you are starting them at the right date.
For starting seeds indoors, there are two ways I have had success with, the first is to start with a good seed starter mix, this should be mixed with 50% vermiculite so it has good drainage. Spread the mix thinly in a tray and dampen it with a fungicide such as NO-DAMP by Plant Prod. (Follow directions on label). This stops the fungus that can form at the spout base that cases the seedling to root off at the soil.
I always use zip-lock Baggies to start my seeds. They are cheep, you can write on the baggie with a permanent marker what it is and date of planting, they do not take up much room, and can be opened and closed easily so you are able to a just temperature and moisture levels. I also find is, I can open the top and plants can grow on until they are planted out Also by tearing the bag open at planting time, there is less root disturbance. Place some of the soil mix in the bag, plant seeds to the depth noted on package and zip up bag. Make sure the soil never dries out or is to wet. Misting the surface with the No-Damp solution can do this. When they have their first set of true leaves, pick out the weaker ones unless this is a package of mixed colour seeds because sometimes the different colours produce different size seedlings.
The second way I have had great success is by not using soil at all but by simply using paper towel.
I soak several layers of paper towel in warm water, wring out the excess water, and fold the seeds inside then put it inside a Zip-lock baggie. I can put a lot of these bags in one clear box. They take up less room, they are easier to carry in and out to acclimatize them to outside conditions, they do not get dampening of decease and as the plants grow I just open up the baggie and set them in light. The only thing you have to remember is to mist the towel so they do not dry out.
Usually a package of seeds holds more then you can use. Why not join a seed exchange and trade for others you want.
When it comes time to transplant to their permanent spot let the plants adjust to the outside by placing them in the shady spot that is protected from winds, with the bags open. Slowly increase the time they are outside over the next week then they can go out to stay. Rake the soil surface to break it up again and plant and space according to package firm around the plant base, water in well, add surface mulch to deter weeds and hold heat and moisture.