I've had a few of them: Agility- Do the Barbarian course until you reach level 52, then do an outdoor course. Food should be three food items that boost agility levels, including some tuna. Only bring a spotted/spottier cape. Alternative is to fish for flying trout, salmon and sturgeon.
Thieving: I believe that the Thieve's Guild is the way to go but I don't own 70 thieving, so I'm not 100% sure. Slayer- Do Smoking Kills quest if you haven't already. Use either your highest or second highest leveled slayer master you can, but always the best every five tasks for more Slayer points.
Farming- Do runs about once an hour Try to fit in at least one a each day, even though you only can get on for 15 minutes. Herbs can be a good investment however, some are more for investment and are not necessary if you want to be extra frugal.If you want to know more about product information can go to https://www.rsgoldfast.com/.