Hi , yes a few tips for you , first don't use sugar (unless priming) in your brews , that will be the main reason why it tastes that way , using more expensive kits are best as no sugar needed . Watch out for old kits , liquid extract is great unless it is old , fresher the better. Temperature control is very important keep it constant and between 18 to 22c , too warm will risk off flavours . But if you want to improve i would chuck kits away and go for extract brewing , dried malt extract , good yeast , hops of your choice and profile of your making will make better beer .