Head to the Cooper Dean Roundabout near Bournemouth Hospital. On the opposite side of the Wessex Way to the Toby Carvery there's a bus stop on the slip road where cars join the dual carriageway. It's an ideal spot to wait for a lift to Salisbury, and if you can get to the A36 on the west side of Salisbury you should be able to find a lift to Bristol.
North towards Southampton, London (M3)
From From Poole or Bournemouth, take the bus M2 until the stop at the corner of Ashley Road - North Road, from there walk in direction of Sea View and walk Sea View road and further north on Ringwood Road. After about 1-2 miles you will be at the corner of Herbert Avenue and Ringwood Road and you can hitch just before the bus stop facing the Shop-Post Office. If you go up Ringwood Road just about a mile further, there's two more roundabouts - if hitch after the last one (where there is a bus stop) you're on the main Ringwood road where all the traffic passes you by. The best option is to accept a ride at least until Southampton Services although there might be some potential spot along the road to Ringwood before the motorway starts.
Within the conurbation, Wilt and Dorset More bus services M1-M2 does connect downtown Poole - Bournemouth - Christchurch at about every 10 minutes from 6am until midnight. The cheapest fare ticket to buy to use that service is to ask a More day rider which costs 2.20 pounds (as of September 2007) and allow you to use the M1-M2 all day long as many times as you want. This ticket is actually cheaper than a return and often the same price than a single, if you don't plan on using it anymore, simply leave it at a bus stop for another passenger.
From Poole towards inland, there is also the services M4 and M5 who would offer a similar service.
From Poole station towards Wimborne, the Wimborne flyer bus runs every 15 minutes as a fast service with that northern community for about 2 pounds.
Around Bournemouth, Yellow buses are completing the network, with even a bus going into Poole. A day ticket is also a cheap option if you want to travel with that company.
Wilt and Dorset offers also a 'Explorer ticket' which enable you to take the whole service within Dorset, Hampshire and Wiltshire for that very same day. That ticket cost about 6 pounds which can be considered when planning a journey to the country side.