I have a migraine brewing at the moment so if I leave anything out or ramble and not make any sense I apologise.
Honestly in my experience I have found that just 'feeding' and empty tank is insufficient to cycle it. If you have a product such as Stress Zyme or Nutrifin Cycle then along with the established filter material you should be able to add one or two small hardy fish with in 24 - 48 hours. A word of caution though if you are running two filters and the non established filter is more powerful the the established one then it can cause Ammonia to rise in the water.
If you have a local dedicated aquarium shop they should sell a small bottle of liquid bacteria that you can use to 'seed' the new filter material for a couple of quid. It's well worth it as new filters can take up to two months to become properly established.
Weekly to begin with changing to fortnightly or even three weekly water changes once the tank is doing well should be enough to keep the water quality at it's best for your fish, so a testing kit isn't a necessity (most aquarium shops will test you water for you for a small charge) however it might be a handy thing to have should you encounter any problems just to assure yourself the water is fine. Remember to only change a quarter of the tanks volume.
You should purchase a gravel vacuum as they remove all of the crud that collects in the gravel and in turn lowers the water quality. It doesn't have to be one of those expensive electrical all singing dancing ones. I only use an manual one that cost me about £4.99. When performing water changes you have to remove the water from the bottom of the tank as this is where the nitrites and most of the ammonia settles. So removing water from the surface won't actually help to improve the quality.
After you have purchased your new fish you have to float the bag in the tank for 20 minutes so they water in the bag can adjust to the temperature of the water in the tank. Fish don't like massive changes in temperature.
You may experience a bacterial bloom in your tank for the first 5-10 days, the water will go foggy. This is not a problem for the fish, it's just an explosion in the number of good bacteria and will go away by it self.
I think that is everything. It can be a bit daunting at first and you'll think you'll need a masters degree in Chemistry, but once you get everything spot on it gets a lot easier.
If I have forgotten anything or you need mroe help let us know.