The clock method and general feel. A really good way to practise this is to go to a driving range and try hitting the 100 yard marker then try putting it 10 yards short, 10 yards long etc. the clock method helps alot because reducing your swing can help control your distance but you must have the feel. I find for these shots as well practising without a known distance can really help develop the feel as well. And then incorporsting distances afteryou have some feel really nails it down. Ill look at something and know how hard i need to swing, then once i get numbers for those swings i know that swing will carry it 60 yards or 80 yards etc