Do it right the first time and you will be much happier. What type of filter do you have? I prefer Eheim canister filters. What type of light? I recommend a glass versa top and LED lighting (I'm using Finnex). Type of lighting also depends on whether you want live plants. Starting off with live plants, assuming that you aren't getting plant eating fish, will go a long way towards good quality water. The best substrate in most circumstances is pool filter sand. Just make sure that you cycle your tank before adding any fish and choose your stocking wisely.