First, most bowhunters track their deer way to quickly. Always give a good shot one hour or even two. If its not a good shot or your not sure, give it 6,8 or 10 hours before you try tracking at all. If its in the evening, just wait till morning. You can't push the deer at all.

Four hours isn't much when looking for a wounded deer. Get some more people to help and spend the whole day (10-12 hours). You said your blood trail was weak. Weak is one spot the size of a pin head every 25- 30 yards. But your deer needs to be dead first or you'll just push it. Thats why waiting is so important!

You wanted to know how to not have this happen again. Go shoot from your stand (practice), and set limits on how far you'll shoot. Maybe it will be only 10 yards! Set your limit where you have 100% no problem with perfect kill shots.(even if your shakey) Last follow my advice on tracking.

Start over from square one....Good Luck!

PRACTICE....PRACTICE....PRACTICE......SUCCESS!