In the general guides section there is a guide by Laura on "dailies" shops you can buy stock from and sell on the GE for profit, following her guide completely will rake in around 1-1.4 mil a day. Combine that with any other money maker and in a day you have enough to start MTK. RSwiki has a chart that updates based on the GE To let you know what the most profitable things to put your workers on are.
After you build up your cash for a week off of that get involved into herb runs for sure, you should have enough for the seed investment. Don't do snaps though unless you have scroll of life or like higher risk. Herbs like toadflax or kwuarm etc will net you about 100-150 k profit a run and you will make even if only 2 patches live. Always however plant ranarr/snaps/torstol in your My Arm's patch as it can never die.
Later you can get into flipping but start with this.
And as others have been saying slayer!
Lauras Daily guide
This looks very promising, thanks!
I've got a few goals now too, it seems this new summoning skill is quite useful. Thanks for the tips & links guys. From what I'm seeing here, it looks like my best way to go would be to follow this guide for about 1250K then go onto kingdom management for more profit.
This will be my long-term goal
slayer to get your combat stats up
get 85 dg
frost dragon until maxed combat
dks/tds/bandos til your bank explodes