I do this, and have planted seeds many years old with little obvious change in the germination rates. The seeds need to be dry and kept dry. And, clean. In fact, for some seeds, a cool period (winter) is beneficial towards germination later. Ancedotal evidence suggests that you could get 10+ years of good viability for properly stored seeds.
I start most of the plants that will eventually get big indoors using peat pellets (tomatoes, cucumbers, peppers, etc). Once the roots start to show at the bottom of the pellets, they are transferred into a larger container with peat + perlite until they are large enough / sturdy enough to transplant outside. Avoid the ceramic pots, you want something that makes it easy to remove the entire root ball when ready.
For smaller plants (corn, radishes, basil, thyme, carrots, beets, etc), I just direct sow these into their final location.
When starting a grow indoors, you will need the sunniest spot you can find or, alternatively, a good grow light (you get what you pay for here). When transferring the indoor starts outdoors, depending on how much light they'd received, you may have to acclimatize the plants to the higher light intensity. Some folk will bring the starter containers into full sunlight for a couple of hours a day over the course of a week or so prior to the final planting spot. That is important if you don't have a very sunny location or grow lamps. Personally, I try to emulate the intensity of the sunlight indoors and just plant them outside when they are ready (sometimes they'll stress out for a short period if it's really hot and clear). Emulating sunlight usually means a fancy fixture that can produce around 1000 PPFD of intensity at the plant canopy and/or a greenhouse.
Number one mistake for those starting their own garden the first time...over-watering. That kills many plants, roots do exchange gas. And, fungus can stunt a plant in an overly moist soil. This is one of the reasons to use small starting containers since it is easier to control the moisture. Only some plant genotypes are tolerant to the lack of oxygen exchange at the roots (kratky lettuce, for instance).
Most other mistakes you can recover from. Avoiding most errors simply comes with experience.
