Had to bump this thread because it is a super important topic imo
I find training two tasks at the same time sometimes helps. Lately, I have been High Alching while doing agility. It keeps my brain so occupied I have no time to look at the xp i've gained.
Sometimes i'll quest and either high alch or fletch darts while i'm running. Some of the long quests are such a drag to get through because of travel, its nice to have a way of keeping your mind working hard. I find if I afk too much I lose interest.
Keep your mind busy and don't focus on one skill too long. If I have 2 hours to kill, I'll train agility and magic for an hour, then maybe ill chop wood and fletch for an hour. I like diversifying my training