Replace sparkplugs and sparkplug (ignition) wires with quality equipment and reasonably often.
Ask your mechanic about the quality of all equipment you’re currently using. Only buy quality equipment that improves spark. Don’t buy any ridiculously inexpensive plugs. Replace traditional center electrode plugs with superior ones (fine wire or other).
Ask your mechanic if you could replace your standard plugs (iridium or platinum) with double platinum, copper-alloy or gold-alloy plugs. There have been claims of better combustion and power increase with these latter, more expensive plugs.
A word of caution: Some of the expensive plugs need more electricity and therefore demand it from your system. Some electrical systems may not last as long with this change, which may mean a few minor updates and replacing your actual plugs more often. If you want to use the gold-alloy plug, ask your mechanic: Can your ignition wires, coil wire and coil handle the increase in demand and heat? Will your cylinders build up too much pressure from the extra heat? If they can handle the pressure and you update your ignition wires, then you’ll be set to go.
If you want enhanced performance and superior fuel economy, changing to superior plugs may be for you. If not, buy the best platinum plug for your vehicle.
Ask your mechanic about widening the gap between the center and ground electrodes of your plugs to get a better spark range. Note: Unless you’re a week-end mechanic, I don’t recommend doing this without the help of a professional.
Some sparkplug wires, although inexpensive, will cost you more money in the long run. Look into more costly wires that offer a good (ohms) resistance. Replace corroded ignition wires as soon as possible.