Normally seed packets contain a lot more seeds than most people can use. However some seed are now sold on a tape system, just like a rolled up tape with the seeds spaced out at the right width for growing. Just bury the tape at the depth listed on the packet. This will save you dropping too many seeds in one spot or losing them.
With flower seeds for annuals I have tried putting them into seed trays, very small ones just to start the plant off. When I do this I open the seed packet and move a few seeds at a time away from the others and put them onto the smallest spoon you have. You can regulate very easily how many seeds are on the spoon and get very accurate by how many seeds you place into the seed tray.